Spoiler: Tyson Being Sneaky
Your actions go entirely unnoticed by the researcher or your fellow trainers. You lift the cloth and see that the placard reads AUDITORIUM 3, then, doing your ninja heritage proud, slip seamlessly back into the crowd and enter the room. It would seem you have not been mislead or sorted incorrectly, you are indeed, in the 3rd auditorium.
You are now in the room, your antics have not deprived you of the opportunity to choose a seat, converse with other trainers, or anything else you wish to do.