I didn't think many campground's free wifi was all that "secure" in the first place.
If I get my own personal password, then that adds some security.
If everyone in the campground gets the same password when they check in, and they only change it once a month, then that ain't so secure.
Somehow I get the feeling that the campground wants to discourage people from using more than one device at a time so they don't have to add bandwidth - but I am not technically astute enough to know if that even makes sense.