Mine has been off since I installed my FASS 2 years ago with out problem. Only things I did was 1) pulled the fuse to the fuel heater circuit and 2) covered the harness for the water in fuel light plug with plastic wrap/rubber band.
I removed the fuse so there was no short when the weather got cold and the circuit energized. I covered the heater plug because when I would run through the car wash, water got into the plug and caused the light to light up for about 15 mins. No problems since. No problems with the canister being removed from the block either.
Hope this helps
J-