Years ago, I used an early polymer holster called the ''Snik''. It had a suede lining and retention was simply a cut in the plastic that curved into the ejection port of a 1911. When you drew the gun, there was an audible "Snik'', hence the name. It was OK for competition, but wasn't really "snatch proof" from a tactical POV.
The locking gizmo on the Serpa is easily disabled and with the tension screw, retention is not an issue for sporting use. But - one site I visited said that several Serpas were broken off their belt attachments during police "gun grabbing' training. Burly cops had no trouble doing this, so it appears to be a design fault.
What is the IPSC ruling on this holster?