[brucepick]

Hmmm.
How about we limit it to two clicks?
To be done at a slow fill rate (see comments on that below).
That should prevent filling into the evap system, while avoiding seriously incomplete fillups.

If there are notches on the squeeze handle, we can specify the slowest filling notch. If there are no notches, then squeeze position is up to the squeezer. The incentive for both filler people would be to squeeze gently for a slow fill.

Granted - this procedure would not enable a person to fill the tank right up to the top of the fill pipe. But I think it would be much more reliable than what happened to UltArc, and probably to others.