How common is silicone caulk usage by manufacturers?

westend wrote:
Silicone is an excellent sealant between two surfaces held in compression. It doesn't tolerate sunlight, weather, or movement very well.

Agree. I use silicone only to seal mounted fixtures that may need to be removed, as a gasket, if you will. I prefer quality marine polyurethanes for permanent aluminum and fiberglass installations and joint sealing. I've had good results with Dicor on the rubber roof and Eternabond or similar "tapes" for rips.