> Under what conditions are you allowed to use it and it not be abuse?
If your plan wasn't to return it from the start, then it isn't abuse. This seems pretty simple. In your original example your "friend" was planning on using GPUs to test and then return them. At no point was he planning on keeping this purchase.
Now, I will say if you're friend bought 3 GPU's with the plan to keep one and returned two I would say that's not abuse, but there are certainly better ways to try before you buy.
If your plan wasn't to return it from the start, then it isn't abuse. This seems pretty simple. In your original example your "friend" was planning on using GPUs to test and then return them. At no point was he planning on keeping this purchase.
Now, I will say if you're friend bought 3 GPU's with the plan to keep one and returned two I would say that's not abuse, but there are certainly better ways to try before you buy.