That's the whole point. Collection of information such as fingerprints, photos, DNA, etc. isn't a choice or an action on your part. They can and do take it by physical force if necessary.

The information within your brain may be encoded in a physical state, but the information in your brain isn't testimony. Testimony is making statements. The the privilege protects you from being compelled to make a choice that is against your own interest. It doesn't protect the information, but rather your liberty to not act against your own interest. For example, the information in your brain regarding a crime can be sought by interrogating others who have the same knowledge. The difference is important. Giving testimony is an act, and that is what is protected. The goal is to preserve your freedom to not take actions that go against your own interest. Consider further the nature of privilege. You do not simply have a right to keep private any incriminating facts- your right extends to your action only. You have the right to not speak. That is all. The right is not purely against divulging damaging facts. The right preserves your freedom to remain totally silent. If you give that up, you give it up completely. You cannot, for example, give testimony in your defense, and then refuse to answer questions that are incriminating. At that point, you would be compelled to answer them, even if you didn't want to. It's the action itself that is protected, not the information. Keep in mind, however that testimonial privilege is not one's sole protection against intrusion on privacy. The right to privacy is rooted in the fourth, not fifth amendment.

Actually, it isn't. Testimony is different from biological facts about a person's body. Logically, under that interpretation, one could not be placed in a lineup, photographed, etc., even with a court order or a warrant. Like it or not, in the eyes of the law, there is a balance between our individual rights and the interests of justice. Under this definition of testimony, there would be virtually no possibility of convicting anyone of any crime. No fingerprints, no blood, no DNA- even cameras and eyewitnesses couldn't be used, since the appearance of the suspect for identification purposes could not be compelled under any circumstances. The issue is one of whether the evidence is testimonial or physical, and DNA and fingerprints are physical. That is not to say I support the idea of mandatory DNA gathering for those arrested, however. I think that it should be treated like any other search, and that a judge should decide in each case whether or not it is proper to compel the test.

If it really bothers you to wait, then don't. The store employee has no arrest powers, especially given that he has no knowledge that you have committed any crime. They cannot detain you without opening themselves to lawsuits and criminal prosecution. You have every right to put your receipt in your wallet, tie your bag, and head out the door. They can't stop you or force you to show them anything before you can leave. On the other hand, they can tell you not to come back, and have you arrested the moment you step back inside the door. Note that this is not legal advice, and I base this solely upon knowledge of the laws in my own state. Things might be different where you live, but I doubt it.

Much better! I particularly like Jumbled Jalopy.