It strikes me as odd that most people seem to consider the radio adjustment of watches as a neat and useful feature, and that no one seems to think about the security implications. What I mean is this: radio adjustment gives to an (untrusted) third party the power to adjust your watch at will. This third party could be malicious, but it may simply be incompetent: if the adjustment service broadcasts the wrong time, your watch will start displaying garbage. Worse: since this adjustment system cannot usually be deactivated, your watch will keep reverting to the wrong time until the broken adjustment system dies off for good.

I don't know of any real-world situation in which watches became useless because of something of this kind, but I don't find it that unlikely. In the meantime, I'll rather stick to watches I can control and adjust by myself and avoid unneeded interference from outside services...