I think that this has only hindered a few cavers- I know of a group of tennessee cavers that left for mid mexico yesterday- planning to stay for nearly a month, and there are a number of trips that left from the Austin area over the past couple of weeks. My trip changed from Mexico to Bermuda, only party due to security issues in Mexico- NORTHCOM announcing that half the country is off-limits to military personnel didn't help the situation any.