We lost our sweet Polly, our camping companion (dog), last Christmas. Gnocchi, our new kitty came to us that October, and has taken over the camping companion status from Polly. I never noticed ...
I'll bet if you tell the CG that you saw a 'stinkbug' in your RV, they would charge you the pet fee. If I had an 'invisible' indoor pet-I would 'forget' to mention it at check-in.