Attaching solar to roof

Buy flexible panels and glue them down.

As above, I wouldn't. The only possible solution is the tape, which is fastened to the rubber membrane. Not exactly a solid enough foundation for my peace of mind.

I don't know why you can't drill holes. There must be a hundred already.

If I couldn't attach my panels in a manner that involved screws, I wouldn't have solar on my roof at all. Once sealant was applied below, on, and above the screws, perhaps the screws could be removed and the panels wouldn't blow off, but there ain't no way in hell I'm relying on double stick tape or sealant alone to hold my panels on. I guess I could make some sort of metal contraption, screw it to the walls, and have it go over the top of the trailer, but there's no point when I can just dip a few screws in sealant and secure them properly.