There's millions of houses in the USA with hot water heaters that are electric and gas. Never heard of a bad one yet. Yours could be bad right now and you wouldn't know it until your flying high. Wonder how often people actually check their relief valves? Why should this case be any different. I would be more concerned with the casing than the relief valve. When was the last time you checked yours? And even if you check it that don't mean it will blow when needed.
FOREST RIVER FW 8524RLWS
2010 FORD F 150 5.4
#1-18' Nomad #2- 20' Mallard #3- 27' Sunline #4- Four Winds C #5- Innsbruck 40' PARK # 6- 28' Amerilite #7- Forest River 26.5 FW ( 1st FW)