Tripping a GFCI is a problem. If you do anything other than fix or replace your charger, you are asking for trouble.
Saftey 3rd is a joke for the race track, not the home. I just want to make this clear. Fix or replace the charger, don't work around safety, working around safety translates to danger.
Now you know. The decision is yours.
I really see no realistic safety issue. One would have to try very hard to get shocked from a charging Zero, even without GFCI. The frame is grounded to the AC plug (when not bypassed) so that makes the frame safe to any other ground when the stock 3 prong plug is used.
Now with GFCI and bike's ground bypassed, what happens? . . .
If one comes in contact between the hot terminal of the AC plug and any ground, the GFCI will trip. If the bike is involved here or NOT. The GFCI is in the OUTLET, not in the bike.
IOW, the GFCI will STILL WORK NORMALLY. The GFCI is in the OUTLET, not the bike, and the GFCI in the outlet is NOT bypassed in ANY way. Even if the bike is not grounded. GFCI does NOT even require a ground to work normally. Unless when we are the ground path to the hot wire, which causes it to trip, as it should.
Get between hot and ground of a working GFCI outlet and it will trip no matter what you do at your bike, frame of bike grounded or not.
So where is the real safety issue here, since bypassing the frame of the bike has NO effect on the outlet's ground fault protection?
The GFCI nuisance tripping is simply that, a nuisance. Since ungrounding the bike has no effect on the GFCI at the outlet, the GFCI will still work normally, even if you somehow try your very best to get zapped at the bike. For us to try to get the shock, with the bike involved or not, it will cause the differential voltage to trip the GFCI at the outlet.
The bike has no GFCI. It's all done in the outlet. And as long as we do not modify the outlet itself, the GFCI will still work as it should, no matter what we do to our bikes.
I think the very best argument one can make on the opposite side is that having both, the bike grounded via the outlet and the GFCI outlet is a type of double protection. IOW, if the GFCI is broken and will not trip (which can and does sometimes happen) the bike frame is at least still grounded.
-Don- Auburn, CA