Do you, as a judge, have any problems with players using perfect fit or other sleeves which allow your players to sleeve their sleeves? Obviously all the cards need to be sleeved exactly the same, that's not the question. Just double sleeving in general.

According to the Tournament Rules, 3.10, I don't see any problem with them, but my TO asked me to get an answer before a tournie coming up at her store next month.

Any opinions?

There's absolutely nothing wrong with double sleeving, triple sleeving, or even sleeving with top-loaders as long as the cards aren't marked and can be shuffled without assistance in a reasonable amount of time (ok, so, admittedly, that last one might be a bit of a stretch…)

Sean is correct, double sleeving is legal.