I have thought of getting a S&W sigma for the cheap for an airline gun for the same reasons you stated. Looking for a good deal on one.I bought mine new for less than $200 out the door. This was in about 1996. Very low 5 digit #. Extractor broke in front of pivot pin after about 600 rds. KT sent me a complete new redesigned top end - barrel, slide, springs. No probs for a few years. Started getting premature lock back (with Gold Dot +P). KT upgraded the gun to new standards for free! By the way BOTH trips to the factory were free including shipping. Even though it's still not pleasant to shoot it is 100% reliable and reasonably accurate with anything.
I use it as my airline travel gun. It's reliable and very size efficient (empty 14oz with 11 rd capacity). I wouldn't get TOO upset if it were stolen by a carousel pirate.