Chris - I am glad you received some documentation back concerning your requests for information.
However, the following passages do not give me the warm fuzzies...
First, Mr. Soghoian asks whether TSA may require a passenger to produce a form of identification (ID), such as a Federal- or State-government-issued ID, in order to fly domestically. TSA has statutory authority to establish such a requirement. To date, TSA has not implemented this authority.
As stated above, TSA has authority to establish such a prohibition, but has not done so to date.
Both of those quotes (emphasis mine) tell me that TSA has plans to implement this at some point in the future, probably near future given the comments of Skeletor and his minions of late.
TSA's receipt of this information is within its authority and does not violate the Privacy Act.
In other words - if TSA asks for your information, you are within your rights to require a Privacy Act notice filled out, since they are a Federal entity and are required to do so under the conditions outlined in the Act. However, if they really want your information, but don't want to comply with the statutory requirements of the Privacy Act, they can just call a LEO over and get the LEO to capture your information and give it to them...bypassing the Privacy Act altogether since the LEO is not a Federal resource (with some exceptions - the Metropolitan Airports Authority police at IAD and DCA are actually Federal LEO).