No, but I don't surf Scubaboard at work. I've got a plate full 3 average engineers working full time couldn't possibly finish anyway, so I never have 'nothing' to do at work - it's just a matter of what's further behind on the list. And, come vacation time, I don't shed a tear that it's no use to take my nationwide coverage pager on vacation, and if we're going somewhere that I can even remotely make the boss think English isn't well understood, the more the better. And, I can always throw in the lower reliability of developing nation telecommunications services before I leave.
My boss never has called me on vacation yet - but it helps to make that option appear as inconvenient as possible. I do always leave the phone and fax numbers, and instructions for international dialing, and say something along the lines of "If you need to reach me, it's probably best to just send a fax if you can get one to go through, and after we're back from being underwater, I'll look it over and try to send one back to you." Works like a charm!