[big-boss]

i AM SURE OTHRES HAVE MORE EXPERIENCE WITH KNOCK-OFF:
i HAVE ONLY HAD THREE CARS WITH THEM VARING HP CARS AND I AM A "DRIVER":
If the nuts are tight and the threads are good they do not back off so the little lock thing is not the issue, that simple. If the left and right hand threads are not on the appropriate side- they will come off eventually- saftey wire will not keep a nut that wants to come off from comming off, again that simple. If the nut was backing off against the littel spring thing- you would see damage to the spring thing for sure.
I still think they were not on right in the first place but you should check:
a. Make sure they are on right sides, duh!
b. Make sure threads are not gone- put a stright edge on the hub threads the tops should all be the samjust like a 18-Wheeler axel check. ( my autokraft had this issue-try fixing that ten years ago)
c. Make sure the wheel back flange fits square against the hub.
d. Try to over tighten the spinner- If it were split it will open up- again just like an 18-Wheeler axel nut or any other for that matter.

Good luck- don't let it scare you even if the wheel comes off the most you would end up with is fame on "Youtube" and some expensive bodywork.

If all is right I would swap front to back and go for a spin.