Two takeaways, one from this and one from my other past experience.
First, when testing whether you can change a price and have a transaction go through successfully, RAISE THE PRICE. If you lower the price the affected entity may come back and say "See??? He's STEALING from us! Lock him up!" If you've overpaid for something through their web interface that complaint and issue goes completely away.
Second, if you're going to suggest that they contact you for assistance in fixing it also suggest other options. My typical handling for this is with hacked websites, so I'll basically say "Your website has problems X, Y and Z. You should work with whoever you have working on your site to resolve these. If you don't have anyone I may be able to assist you, or I recommend talking with a firm like Sucuri.net which has dealing with and preventing issues like this as their primary business. (My only link with Sucuri is having seen some of their folks do presentations at trade shows.)"
> If you've overpaid for something through their web interface that complaint and issue goes completely away.
Or it doesn't, because you have still "hacked them". Doing it in a seemingly bizarre way may only raise more suspicions; obviously you must have maliciously cheated them, since who would give them money?
Please don't put people at risk by giving such "advice".
What I was talking about was the question of being accused of theft (by having completed an order/purchase after lowering the price). This was also in the context of someone already intending to push a transaction with an attempted price change. At that point nothing you do with the price is going to prevent a "hacking" charge if there's going to be one, but you may be able to prevent a corresponding "stole from us" charge.
First, when testing whether you can change a price and have a transaction go through successfully, RAISE THE PRICE. If you lower the price the affected entity may come back and say "See??? He's STEALING from us! Lock him up!" If you've overpaid for something through their web interface that complaint and issue goes completely away.
Second, if you're going to suggest that they contact you for assistance in fixing it also suggest other options. My typical handling for this is with hacked websites, so I'll basically say "Your website has problems X, Y and Z. You should work with whoever you have working on your site to resolve these. If you don't have anyone I may be able to assist you, or I recommend talking with a firm like Sucuri.net which has dealing with and preventing issues like this as their primary business. (My only link with Sucuri is having seen some of their folks do presentations at trade shows.)"