I think a simple indicator which is usually green or neutral could turn red till the next action from the user is taken. Or a whoopie cushion sound is played 8).

Something like this above... The red MoI would turn normal or green once I would hit the cancel button/esc key. The function is not possible because of the imposssible distance. I leave the sound to the imagination 8).
Cheers
Rainer


PS:A dynamic bevel depending on the tightness of the curve would be REALLY cool!... V3 maybe???