I think it was superbee or accumulator, can't remember off the top of my head that believed zaino offered very little in terms of enviromental protection. Long lasting, yes, but no actual "protection".
in my own experience, tuesday of last week a bird pooped on my hood . Its been about 70 degress the past week. I didn't get to wash my car until saturday evening. The car sits outside all day. I have maybe 3 coats of upgp on it. ONR took it off with ease, almost no aggitation. I was expecting there to be some kind of etching, but I could find any. This was under halogens and a led light.
On the other hand, I use OCW on my headlights since it boasts UV protection. A bird pooped on one. Maybe 4 hours went by until I could hit with some QD. Low and behold, there was etching.
Granted there are a lot of variables here, plastic isn't the same as CC, the amount of acid in each birds gut those days could have been on opposite sides of the spectrum, I think some products offer more enviromental protection than others. Put it this way though, we might not know 100% if they protect, but does it to hurt to PUT IT ON? I doubt it. and with wowa sealants that take no more than 10 minutes to apply, it doesn't take away time either.
Weight the options here, save 10 minutes not applying something and have the potential of the enviroment harming your paint, or use 10 minutes applying something that could potentially save your paint from damage. I think the choice is easy.