John, it's not so much the fence behind the 18th green at TOC as the one to the right where the pin was cut for the final day of the 2005 Open.
Funnily enough I was discussing this issue with the course manager at a club yesterday where they have two greens on short par 4s with OOB a few feet from the edge of the putting surface. They are just waiting for the first insurance claim. They have tried all sorts of artificial means, such as planting trees, putting up nets, inserting bunkers on the straight line, moving tees etc so that people drive away from the OOB and then approach the green at more of an angle, but this negates the original Colt design philosophy in which players were encouraged to risk trying to drive the green.
There are a lot of such old courses in the UK surrounded by roads or housing and on an area of perhaps 100-120 acres. This is going to be a major problem. They cannot easily re-route. With much heavier weekday play and golfers hitting the ball farther (and also more wildly) plus a litigious public I imagine that architects here are going to have their ingenuity tested in trying to reroute on tight sites to ensure the club retains 18 holes, and the likelihood of par dropping a shot or two.
The OOB on the clubhouse terrace on the 18th at Royal Troon is a significant factor as you play to the green.