yes and if there is even one hole, then sort of defeats the purpose. assuming it is not large enough for the dead spirit to infiltrate although i seem to recall from scooby doo cartoons that ghosts and spirits can easily go under small door cracks or through key holes so a plastic bag could hardly be a match for them.

OP, damn, that's not fun at all.

I always immediately change into cotton PJ's when I fly. At least I then have a pair of clean clothes for these kind of rare possibilities.