Nope, I use a tirfor too. 2 of them in fact, a 1 ton and a 3½ton, they are surely the neatest winches ever made. The 3½ tonner has a break factor of 16 ton, so even if you pull hard enough to break the little safetypin, it won't let go of the load.
By the way, Tirfor is from Switzerland, not Italy.