When joining the military a person actually forgoes some of their rights, they choose to do that. I choose not to forgo my rights. You may consider it "not a big deal" but I consider it important and am not going to allow it to be done.

If I ever join the military ,or get arrested, then that will be different I suppose, but I'm not going to allow it to be done for no good reason and simply being willing to volunteer my time is not a good reason for me to allow that infringement on my privacy.