Using (official Vex) zip ties in general is perfectly legal; you are not required just to use them for wire management. We’ve used them in place of screws, to hold things at weird angles, to move balls down specific paths, to help on rubber band intakes for flipping caps, etc. In the game manual it even references zip ties as an example of a restraint one might use for maintaining a starting size.
That said, a debate I recall from years back was in fact that quick swapping itself may be illegal (since it could technically be considered a modification of an electrical component). @Karthik did address this at the time, though, and state that it was in fact legal (as teams could use motors that were missing motor screws, and removing those screws was an allowed process for changing internal gearing).
This doesn’t have any real bearing on your 3d printing question, however, because zip ties in and of themselves are legal for regular build use and 3d printed items are not.
As @lacsap stated, if you want something official you have to go to the GDC official Q&A. Everything on the forum is our best guess & opinions only!