A 4 year problem using my MBP @ a Starbucks.

Friends, I come to you begging for your help. My wife and I had two identical white Macbooks in 2007. When we would use the wifi at Starbucks (and other small public wifi networks), it was hit and miss. Sometimes it would work instantly, sometimes it would show the exclamation point on the wifi icon and 2-10 minutes later, magically just connect. Two years ago we traded in the white MBs for two MBPs and the exact same thing still happens. It's completely random. The more I even touch the keyboard, the longer it takes that exclamation point to go away and connect to the network. On occasion it never connects. I went into the console and copied some messages that are generated when I have the exclamation point that may help some of you.

I'm being realistic. I'm a tinkerer. And I tinker without knowing a ton about computers. Since we've had 4 computers all do the same thing, we're both convinced it's something I did. I vaguely remember changing the DNS settings to something Google offers, but you should know that we never have a single problem at our house or anyone else's private home network. It's only these public ones that are problematic. Thank you in advance for anyone who even bothers to look at this issue. I apologize if I'm posting this in the wrong place.

The console messages:

9/2/11 6:15:03.807 PM UserEventAgent: CaptiveNetworkSupport:wispr_detect_http_done:196 DNS failure - scheduling timer to try again in 0.70 seconds. retryCount=9

9/2/11 6:15:04.508 PM UserEventAgent: async_http_read_stream:375 kCFStreamEventErrorOccurred kCFErrorDomainCFNetwork/2: The operation couldn’t be completed. (kCFErrorDomainCFNetwork error 2.)

9/2/11 6:21:51.122 PM configd: subnet_route: write routing socket failed, Network is unreachable

9/2/11 6:27:56.614 PM UserEventAgent: CaptiveNetworkSupport:CaptivePostAuthCheckTimerCallback:1852 Post Authentication timer fired ..

9/2/11 6:27:56.614 PM UserEventAgent: CaptiveNetworkSupport:wispr_detect_redirect_async:424 user-agent:"CaptiveNetworkSupport-173 wispr" url:"http://attwifi.apple.com/library/test/success.html"