Once again the flakeyness of the comment editor means I lose a fair bit of response for reasons I can't quite fathom. If there's something weird going on in the post it's because am trying to copy/paste into it and I don't know what it's doing.

In short, the ability to sneak around with cavalry was rather limited, especially in the context of jumping on artillery. Cannon were not deployed behind your battle lines, but actually more likely in front of them.

The majority of artillery tended to be deployed front and centre for the simple reason that your troops will be rather unwilling to be the first to be hit by a cannonball ploughing through their backs on their path toward the enemy. Cannon can't shoot over your own troops unless they are physically placed above them. Or so far back that the cannon will be severely limited in range and there will still be friendly fire incidents. Cannon ranges are fairly modest as things go. We are deep into the 1800s before we get effective howitzers and they only really come into their own in the 1900s which solves the range and direct fire problem of artillery. Effectively all modern artillery are howitzers and not cannon. The solution to this dilemma of course is to park cannons on a hill or other elevated position, but there is no guarantee you will be able to pick your battlefield. The other issue is that artillery for most of the period wasn't easily moved so if there is too much moving around you might no longer have placed the cannon in a position they could be effectively used. This means there is a lot of jockeying about where a battle will take place and often if you found too good a spot the enemy simply chose to not engage you. Furthermore, as your cannon require good line of sight to fire, their placement tends to be in spots that aren't easily approached without being seen in return. The other side of the coins is that cannons can't easily be moved. So there are battles where cannon change hands several times, even being used by both sides, during the course of the battle.

Another aspect is that until the 1800s battlefields are fairly limited in scope, communications and armysizes simply didn't allow too much spreading around or you risk losing control of your forces. With few accurate maps and no GPS it's not easy to actually sneak around. Coordination wasn't easy in the best of times and successful cavalry actions has several times turned victory into defeat when cavalry troops follow the enemy off the field or end up looting the baggage train. Basically letting your cavalry off the leash too much risks them not being where they are needed. You normally do not want your cavalry to be "behind enemy lines" because that's not where the enemy cavalry is and the end result may be that you are losing the battle due to not having cavalry of your own, especially in the 1600-1700s where the side whose cavalry prevailed in the (usual) cavalry battle on the wings of the battleline could then destroy the enemy infantry centre at leisure.

Sometimes it worked though, in the battle of Wittstock 1636 Swedish commander Banér had his left wing cavalry perform a long circuitous movement while the centre and right attacked with right hook movement that forced the Imperial army to redeploy. This let the Swedish left effectively sneak up on the Imperial army and flank them. Amongst other things according to Montecuccoli capturing the Saxon artillery without it having fired a shot. However, they had had more trouble finding their way and only arrived in the nick of time when the right was about to break and the Swedish force suffered considerable causalities and could well have lost the battle had the flankers been delayed even an hour more or even less. Note that the Imperial artillery at this battle had originally been deployed centrally but ended up exposed as the battleline had to shift.

As to the question of artillery guards, yes they existed, among the first troops to be issued non-matchlock muskets were the guards of the artillery train (due to the firehazards). But these troops aren't exactly numerous enough to stop a determined cavalry charge, their job was security from sabotage and during marches and camps. Being too close to artillery was dangerous, cannons could blow themselves up and there was a lot of gunpowder that could explode so you don't want too many troops too close to the artillery. The cannon themselves are more likely to stop cavalry using canister and grapeshot provided they can be handled in time. As you would deploy cannon fairly centrally to some degree the entire rest of your army was effectively the guards of the artillery. More so the further we go in history, few battles in the 1600s were decided majorly by cannon, but by the time of Napoleon they are becoming battle deciders, AFAIK. The amount of cannon used by armies increased substantially over time. At Breitenfel 1631 the Imperials had about a dozen guns of various caliber, at Nördlingen 1634, 34 heavy guns and 116 light pieces.

Finally, do note that the crew of the cannon could fairly easily escape. Cavalry might not be able to take their time to properly spike the cannon (and that means literally driving spikes into the fireinghole to render them useless for the battle) and of course you might not want to if you are expecting to win the battle and capture the cannon for yourself. There are many examples where the crew can re-man their cannon if only limitedly spiked, or indeed the enemy can use the captured cannon against their former owners like at Lützen in 1632.

Rather than sneaking around the battlefield capturing cannon, the more likely actions was what the Light Brigade were famously tasked with in 1854 at Balaclava. To prevent the enemy from using a captured artillery emplacement. What they instead did was to frontally charge a well emplaced and protected different artillery battery with tragic consequences for the troops. Even so the light brigade did reach the cannon and scared the artillery men away. Temporarily. In other words it's quite possible to charge, successfully (or not), enemy cannon without sneaking at all.