I’m the same as
@soniam and I plan to bring my little REI chair unless someone posts here before i leave that they could not bring theirs in.
I am following the clause that says don’t bring anything that does not fit in a small bag or backpack, and mine easily fits. Last Expo there were people towards the front of the line with huge inflatable chairs and mats, that they’d deflate when the line starts moving.
I think this no folding chairs comes from 2015, first Expo with the basement lines, where a lot of people brought the large folding lawn chairs and then left them in the basement rather than carry them all day. Disney had a lot of chairs to pick up and toss after the basement cleared out.