I have the covers on mine. Last time I was waxing it I happened to bump and pop off one of the covers. It was full of insect nests. Also, just because your weep holes look OK doesn't mean insects haven't built nests up in them. Take a piece of wire and poke it up in the slots to make sure the hole is clear.
2000 Monaco Diplomat 40PBD
2012 Grand Cherokee Limited
2008 FatBoy, three spoiled Great Danes and a cat.