If the stress is enough to rip the slug out of the track, or break the
connector
between clew & slug, yes it is. Been there, done that..... it rips across the
foot
of the sail like a zipper.

Unless your talking about a different type of slug than I have ever seen I
don't know how a big round slug could pull through a 1/16" or 1/8" slot. Ok I
could see the foot ripping along the bolt rope if the sail was old.

If the problem is chafe where the slug is strapped to the clew, then yes
your foot might stay in the track.

That's what usually happens. The strap fails.

The tack fitting is at the other end of the foot, how is it going to help
keep the
clew in place? Loco, you're not an engineer are ya?

I never said that. My point was that the entire foot would stay in place on
the boom. A sail with a bolt rope, even if the clew slug attachment failed,
would be held in place because of tension between the tack and outhaul. My
engineer (simulated in the matrix) brain tells me this.
S/V Express 30 "Ringmaster"
Trains are a winter sport