My fault for sloppy wording. I was supposing for the sake of the hypothetical that the police made it obvious to you personally that they would attack you if you fail to comply.
In any case the ACLU-type advice of "stay silent and don't consent to anything" assumes some strange middle ground, where the cops in front of you are hostile enough to be actively fishing for something to arrest you for, but not hostile enough to just beat you, plant stuff and lie. And, further, that I, a random person who rarely deals with the cops, will be able to correctly sense what sort of encounter I'm having, against police who do this dozens of times a day, who are very scary, and who might be specifically trying to trick me.
Or just to rephrase what you said, the ACLU-type advice is great if you're the sort of person for whom awful police encounters are unlikely and who can lawyer up right away if things go wrong.