I'm not real fond of Starbux anyway, so I was thrilled to discover that my local independent coffeehouse had free wireless internet (unlimited). So, you might look around and see if there's an alternative like that where you are.
As for Borders... well that's unfortunate. I'm not a big fan of doing the T-Mobile thing, but they do have a pay-as-you-go option for $6.00/hr if you're an infrequent user. They didn't have that (that I noticed) when they first started the hotspot plan.. It might be worth it if it works well. I may have to try it the next time I'm @ Borders...
BTW, Hydroglow, the BofA story is a bit scary without even hearing it. I worked in IT for a Bank (not BofA) for about 3 years, and bringing up an access point on the internal network was a termination offense. I got quizzed once about my laptop, not connected to the corpnet, but running a AdHoc node that showed up on the wireless audit. I was "asked" to shut down the wireless bits, even though the laptop wasn't connected to anything. Did you actually get on their network, or did Stumbler just show its presence?
Also, using someone elses network like that may not satisfy your need for free surfing anyway. Once you're on their internal network, you then have to work out how to get back out again if they're using some form of caching proxies. That might also prevent non-web traffic getting out at all. Oh, yeah, and there's that delicate issue of your having "broken in" to their network... Be careful.