Eternabond Tape

I suspect any brand tape or any brand caulking would trap water if water was already inside. I want to trap the moisture before it gets inside.I suspect some of these dealers would like to keep repairs inhouse for profits. As far as brand is concerned I doubt anyone could tell the brand name once it was applied. Once out of the tube the name is gone. However, If someone uses TV ad spray or caulking or silicon on their it is pretty apparent. I've never had a dealer crawl up on my RV roof when I traded it. Private sales? Probably.