Interesting, my black pastel het hypo female is a "squeaker" when she gets excited or stressed. A few times I've thought she was starting an RI, especially since she did have one early this year so I'm a bit paranoid about checking her, but since getting over the last one she's never exhibited any of the other symptoms like bubbles, mucus, lying with the nose pointed up the wall, excessive yawning, etc.
As for the OP, the initial reaction to either a bad shed or a potential RI is pretty much the same - increase the humidity and wait a day or two to see what happens.