A lot depends on how creased the metal is.
Was a similar topic on the landrover forum i use and i'll say the same thing here:
We have insurance which is supposed to protect us against things like this, however because the insurance companies shaft you proper style for any claim whatsoever, your left with the decision: Run, or pay an extra 2,3,4,5,6 hundred pounds for insurance for the next 5 years. The cumulative cost of increased premiums for such an incident could easily be 5-10times the cost of the repair, if not more, for a small incident like this and quite often people simply cant afford it. When you put someone in the position of financial hardship for 5 years (perhaps even to the point where they simply cant afford to insure the car) or doing a runner, MANY will choose the latter.
The other option would be offering to pay for the repair out your own pocket (assuming you can afford it), and avoid the insurers altogether, keeping your conscience clear and saving any increased premiums, but then the other driver might decide to claim anyway (if hes a bellend), and now you've let yourself be known and he has your details your back to being getting boned.
Many years ago, when i was young and had just collected my first years NCB (insurance had dropped from £1300 to £800ish), i hit a car in MacDonalds car park. My electric window motor had failed, so i'd opened the door to collect my food, and placed it on the passenger seat while drawing away from the window. Found a nice space, slotted it into reverse and backed in. Unfortunately the drivers door wasnt shut, it was ajar, so when i swung the steering over, the door swung open, and clipped the mondeo in the next spaces front wing. My first thaughts were "oh s**t thats going to cost me a bucket load if i claim" and the next thaught was "i'm off" and i jammed it back into first ready to smoke it out the car park. However i then noticed EVERYONE was staring at me, people in the drivethru, people inside, the staff at the window, so running was out of the question, as undoubtedly someone would have had my numberplate. I backed into the space and ate my food, waiting for the person whose car it was to come out.
As it happened the wifey came out, looked at the scrape and said "ach its not down to bare metal, and i stoved the back of it into a lamp post last week, dont worry about it" so i got lucky.
I should point out i'm not condoning the actions, just pointing out that when you bring money into it, being nice can often go out the window.
