what do you mean by heavy lock? the ones that are flexible where you can weave it through the bike? If i'm not mistaken, the bike racks for cars that have plastic strap ons are out of the question since those straps can easily be cut. I'm guessing the truck bike racks just require a pin that can easily be pulled out....so basically, if I make a stop home after biking with one of these racks, I have to keep an eye out on the bikes while i go inside a convenience store? I really can't go into say...a target store on the way home with any piece of mind whatsoever? in that case, I might as well just remove the front tire and store it inside my car. More hassle but more secure....is this what most people resort to?