You seem very over concerned. This is a sport and most of us do it for self pleasure as a way to relax. At the end of the day you need to be responsible for you and realize this is probably one of the safest sports to participate in. If someone makes you feel uncomfortable find the match director and let them make a decision.
USPSA rules are for matches. Matches consist of stages and the areas set up for those stages. That is why the chrono is considered a stage. Any bays that are not being used by the match are not governed by match rules. Nothing you listed applies.
I have had great results with the MBX guts so far. I don't losd mags night before a match, I don't let them sit with ammo in them for the ride home from a match. And I don't load full if shooting stages with required reloads. I do shoot 3 matches a month and during the winter and fall months I practice a ton in between the matches. Haven't needed customer service and hope not to need it. Glad to know TTI is an alternative tho.
Single stack is suffering too. My son loves it, but the competition is drying up. Hi capacity optics divisions have crushed the production and single stack divisions for sure.
My Edge has ran perfectly, the operator not so perfect! I am going to get another Edge for my son soon. I like it much better than the DVC that STI has replaced it with.