Louis Rossman over at YouTube has been going over this fuses thing from Amazon. All the fuses he tried from top-results didn't blow until he put 4x or 5x the current rating through them.
Probably not. But precision is expensive. A 3A +- 0.1A fuse will be more expensive to make them a 3A +- 6A fuse. And of course a customer will be upset with a 3A - 2A = 1A fuse so they really make a 9A +- 6A fuse and sell it as 3A.
So if you are "lucky" you can pass 12A though it no problem.
