I am sure you'll disagree with me on this one, as you and I have had some different thoughts so far.
My favorite anchorpoint on a vehicle is spokes on a wheel. All the lockout/tagout type procedures are used as discussed above. Of course, judgement is used per case, doing this with a Smartcar is not as advantageous as using a Ford F-350.
What we never use, any anchorpoint on the front or rear of the vehicle. There is too much play in the suspension that rocks back and fourth, that can lead to damaging equipment on edges. Anchoring on the wheels stays below the suspension, taking that play out of it.
We use a vehicle quite often for rope rescue. We usually wrap the axle, after applying the emergency brake and removing the keys of course. We use plenty of edge protection and make sure you don't wrap around a brake line. We also have placed a trailer receiver around all four sides of our brush truck and bought a pintle hook receiver we can use as an anchor point.
Im out of an industrial setting and we have rienforced bumper mounts for our uni-hoist unit on the back of our two rescue vans (Ford Econoline Full Size). The unihoist also has its own extendable mount and we also have a tripod system.....but we have kind of moved away from using the vehicle mounts..... on occassion we'll still use it in a situation were we can back the van up, but the reality is when we do this our entire equipment moves with it right into the HOT zone of the space.....if we end up having a situation that is an atmosphere concern we could have issues with that....I think in the end taking the time to just set up the tri pod or the unihoist with its mount is much more effective for our particular situations...