I've been doing PK watch stops not quite as long as Craig (cos I'm not quite as old as him

) and I've never had a problem either.
If you understand the mechanics of a watch, you'll realise that it's almost impossible to completely kill it with a very quick and gentle magnetic stop.
Using a sensibly sized magnet with a watch is favourite, and don't repeatedly go for it. After all, remember from your school physics lessons that it's easy to 'magnetise' a needle to make a compass. The same can be done to the delicate parts of a watch.
As said, don't mess with expensive watches just in case. However, all isn't lost. Any jeweler or watchmaker shop should have an electronic demagnetising kit which can sort it out for a couple of quid.
My young bro has a Tag Heur watch, which I know cost him the price of a decent second hand car, and I've 'experimented' with it and PK effects.
The watch has more dials than an aeroplane cockpit, and it seems unscathed after being stopped.
But, if you're dubious, don't do it!
Secondly—on the subject of pacemakers... Before I released my 'Get Fluxed' series of books to accompany magnets, I researched pacemakers pretty extensively. Basically, the pacemaker is fitted with a magnetically operated switch which puts the pacemaker in programming mode. As soon as the magnetic field is removed, the pacemaker goes back to normal. In fact, it won't really do a great amount of harm.
Obviously, this doesn't mean you can try holding a 3" cube of neo next to someone's chest... cos that's tempting fate, but the 'urban myth' as it appears is pretty old-hat.
In fact—here's a true tale... at my main local post office (Shrewsbury, inside WHSmith) one of the clerks, a young lad, has a pacemaker. Although cautious, he has handled many magnets for me, including monster and megabertha kits. Which, incidentally, stick to the counter, and mess with the scales' ability to weigh correctly.
He's still alive, and unscathed.
All in all, I think this all boils down to common sense.