Logging into your bank (or any other HTTPS connection) would be perfectly fine, it's encrypted between your browser and the bank's server so no one is going to see that.
If they knew what they were doing though everything else you did would be wide open to them seeing, including your forum password.
The chances that they know what they are doing is pretty much zero though.. If they kind of knew what they were doing they'd secure the network.. so either they're clueless, or they leave it wide open so they can watch all their neighbours surf the net.
I've often thought about doing that, leaving an open connection and putting an invisible proxy in place so that when someone connects to my network and surfs, they get directed to the sites
I want them to see.. Or replace all their images with goatse.. or turn all the images upside down... or translate all the pages into russian
