The XGPS150 has a free apple shop app which displays the satellite status - something which the apple API blocks apps from accessing.
The fact that this app was not banned from the normally highly anal apple shop suggests that apple don't exactly mind an app talking to a bluetooth GPS
directly.
So in principle another app could do the same.
The problem with today's WIFI situation is that most (and in some countries I have been to recently, e.g. Greece, absolutely 100%
all that I came across) un-encrypted access points are commercial (pay) ones. It would be trivial for the Ipad to check connectivity by e.g. going to a known website and doing a quick HTTP request but currently no retail product I know of does that. In fact apple already have a
web page which seems to be exactly for that kind of purpose
But this is digressing...