Not sure and hopefully someone else will chime in, but I think that
would defeat the purpose of having the moist air:
a) contained, in piping, on its path from the bath to the outdoors
b) not coming into contact with anything that could mold or rot along
the way to exiting the structure - only metal and plastic.
If you just run it up near the ridge vent, mold would ensue. If you
could get it beyond the ridge vent - have the exit tibe go thru the
ridge vent and project outside, that seems ok. Not sure which you