Can somebody take a laptop with a wireless card down there beforehand and see if you get a signal? Are laptops legal during the parade?
I'm in CA and will be bringing a laptop with a wireless card, but won't be flying into DC in time to do this. I am directing your question to Kristinn.....PING!
I believe that Verizon is the only company that has a wireless service able for laptops. You might be able to sniff a RAT WAP if you have the right instumentation.
I'm checking with the Park Service to see if laptops will be allowed in the secured areas on the parade route.