I don't get how a retraining strap is at risk of causing problems, please explain in more detail
I didn't see an answer. I think I know how this can happen:
The retaining strap can "jump" inside the trigger guard during re-holstering. If everything lines up just right (or wrong...) it can catch on the opposite side of the holster. As the user pushes the pistol down, the strap presses the trigger.
I have a very, very old leather Safariland for a Commander that has such a strap. I stuff it inside my pants behind the holster until the weapon is holstered, then dig it out and secure it. I only use it for a "field holster", not for CCW (which is a Galco slide type -- no straps to mess with.)
While this is rare, I've heard of it happening to DA revolvers as well as pistols.
(Also, I've heard of this happening with a leather thumb break that curls in from the outside if the user doesn't hold it out of the way while re-holstering. The friction-fit leather or Kydex have no straps and probably aren't as likely to do this, though a molded edge could catch a trigger if the user tried really hard
)
As long as the thumb safety is on, a 1911 should be immune to this. (Other than the profanity that it causes, it shouldn't cause an AD.)