The way it's been explained to me, during the days of the Gold Standard, when countries paid for their debt in gold, they would very rarely actually transport the gold from country to country and, instead, simply earmark their own gold supply as now belonging to the other country (e.g. when Germany paid Britain war reparations, they simply marked it as now belonging to England and then sent them an equivalent to an I.O.U.) Please feel free to correct me if I'm wrong.
So, let's say I'm a country in the 1920s who owes reparations to another one. What's to stop me from saying that my country has discovered a large pile of gold, doctoring photos to make it appear like it exists and simply paying my reparations using this nonexistent gold supply through I.O.U.s?
Reparations were not usually only paid in cash or gold (or gold backed cash). In the case of Germany after WW1 for instance coal, machinery (particularly ships), timber etc all made up the payments as well as a system of bonds. Coal was really the main one though.
Germany likely would not have been able to doctor photos or falsify accounts as their banking system was run under the auspice of allied occupiers enforcing non-german staffing quotas in the management of many institutions involved. This is not untypical of counties after losing a war.
Even if they did falsify/change/increase suddenly the gold reserve numbers, and allies believed them because hypothetically they did a lax checking job and were very trusting, its unlikely the allies would have let them changed the 'gold' equivalency discussed during the treaty. The allies knew that Germany would either:
or
given half a chance.
The allies therefore did not accept 'paper Marks' (immediately taken up after the war) - only 'gold Marks' (there is are exceptions regarding paper marks given to the occupying force in the Rhineland). The Germans did try and skirt this however with various tactics - selling paper marks for other currencies and inflating/meddling in forex + fixing dated contracts (for instance for reparation timber from suppliers in paper marks before giving it to the allies) and then hyperinflating the hell out of paper marks. Things like this.*
So countries were keen to your point and did take steps to make sure all payments were properly 'backed' meeting various degrees of success.
*this is an area of some debate
Nothing.
The gold standard was/is/always will be total 🐂.
Nothing.
The gold standard was/is/always will be total 🐂.
Nothing.
The gold standard was/is/always will be total 🐂.
Nothing.
The gold standard was/is/always will be total 🐂.
Nothing.
The gold standard was/is/always will be total 🐂.