I don't even depresureise it. I suppose if you go up and down in altitude a lot it might be a problem .. but otherwise - no !
----- Unless you are flying it! then you have to drain it (easiest to let it burn off all the fuel .. you get some traped in the tubing otherwise), then let it air for 6 hours minimum, wrap it in some absorbent material (paper), put it in a plastic bag and seal it. If you don't air it for 6+ hours then they offer mixing the fuel wiht some low flash point fluid (cooking oil), drain etc ...
Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S