Hmmm. I've used butyl tape, but that looks interesting. I have an entire trailer that needs all it's hookup ports and windows
Just for clarification, I do think butyl tape does a great job and lasts a very long time, but trailers do occasionally leak, and depending on butyl tape creates a single-point of failure that can allow that to happen.
Installing a curb around any roof features creates a second engineering feature that would also need to be overcome. Perhaps this is silly, because I'm not creating a curb or gutter for our windows
and other through-holes on the sides of our trailer, but with so many reports of people who have leaky fan vents, this seemed like a good idea.