That's actually pretty interesting, could you elaborate on the source?

When it comes to ransom, I could potentially give you an answer. Wars were fought a bit differently in the Middle Ages and if you were a high-status knight, or just came from a wealthy family, death on the battlefield was not the only outcome in case of a lost fight. In fact, with enough luck in avoiding serious wounds, you had a good chance to plead for mercy and being taken prisoner.

There was a system in place that made taking defeated enemy knights prisoner and exchanging them for sizeable ransom. Knights (or at least their families) were landowners and thus able to produce enough money to buy out their freedom. They were held prisoner until the money to free them was raised by their families, from their lands, etc. Then the knight would be allowed to go back home.

It was highly profitable and ensured a degree of protection to knights, especially if they were recognisable (by their coat of arms and colours) as members of prominent families. Knights were in and of themselves very valuable - a knight came with not only armour and a sword, but also extensive training, horses, retinue, and sometimes a squire or a team of footsoldiers to support him; a single knight could have been a whole enterprise. It was much more affordable to buy out the knight than to invest in replacing him.

If knights bet their ransoms, exchanged on the battlefield for their lives, in tournaments, that was waging some serious amount of money, not to mention potentially their get out of jail card.

But then again, tournaments were an absolute craze during the High Middle Ages and I can absolutely picture this exact situation happening. I'm just curious if you remember the source where you found the information, I would love to check the context.

Edit: On second thought, the protection probably didn't really extend to all knights - just the ones from wealthy, noble, and prominent families.