This is done by 95% of snake owners that have Glass Aquariums so as far as the RI info not sure.. Im sure that has to do with someone trapping bacteria without air/vents. PVC enclosures manufactured for snakes only have a couple Vents on each side. Just like tttaylorrr explained is the correct way for a DIY. I have a CHE on a tank I use for quarantine so about 2/3rds is covered w/foil & the far end open for the CHE. Another tank I have (40 gal Long) is completely covered in Plexyglass with a vent on each end. 100% ok