Good catch.
The camper is pretty tall and low hanging branches took 3 of the push in replacement caps. I was in a RV dealer and the customer ahead of me was buying a metal vent cover. I didn't know they were out there, so I ended up with one as well. Into its second year on the roof and it has some dings, but it is still there. Metal wasn't much more than plastic, but should last longer.
Water getting into tank in freezing climates is not a good thing.
Brian
2014 Chevrolet 3500 CC 4X4 Duramax, Tork Lift Tiedowns, TorkLift Fastguns, Superhitch and supertruss
2009 Jayco 213 SOLD
2008 Bigfoot 25C9.4