I'm a criminal defense attorney (barred in Virginia), and I'm a good enough lawyer to tell my clients not to invite charges for idiotic reasons. The best outcome is no charge.
Now with that said, let's say I already have an Amazon gift card that has been used. Does it work like it does with say Target and I can just add on to the value (of $0)? That is an interesting question to me.
Definitely wasn't suggesting someone try it, by any means.