That was like the biggest thing i learned in computer class, that i already knew in 2002 or so. Later myspace became a thing, and everyone had a myspace name. Then facebook and some people used their real name. Then facebook asked you for your phone number, and i thought: well, that's silly, who in their right mind would do that. Turns out the answer is everyone.

Also on Android press the power button and volume up button simultaneously, and then press lockdown.

Five times wanted to set off an emergency service call and sound the alarm 🚨 YMMV (Pixel 7)

You can be polite and decline consent without resisting. "I do not consent to any searches or seizures". If it's taken from you illegally then anything they find is inadmissible in court. If it's taken from you legally, ain't shit you can do anyway.

"what's a phone?"

"I don't know why my fingerprint isn't working" (biometrics are disabled)

"I don't remember my passcode" (it's a pattern input field)

"The guy at the phone place changed it for me"

"It's never really worked right."

"There's no Google on it tho." (What does this even mean?)

"Who do you need to call anyway?"

"Can't you just use your own phone?"

Just act like the dumbest creature on earth.

Depends on local laws, but if the cops ability to seize your property without warrant isn't protected by local laws:

Ask if they have a warrant and if they don't then take your phone oout and power it down, then put it back in your pocket and tell them they can direct complaints to your lawyer because you're not handing over any devices.

If they seize it without a warrant then you can sue the department, although if they have reasonable suspicion then you won't have much luck.

in such a way that things end up worse for you?

IANAL. This is what they want you to think, "just do this and it'll be better for you". It might be a short term hassle waiting for the drug dog, or being arrested while they conduct their investigation. But long term it's the court that matters. And the court will throw out anything obtained illegally or the cops do illegally.

Cops are not there to help you, they just want to find someone to pin a crime on. The only one that will help you is your lawyer. Stfu. Don't talk to the police.

Just the act of refusing makes the act of seizing your phone legal or not. If you legally give them your phone by your own will, they are able to use all evidence they find in the courts. If you deny to give them your phone, and they seize it anyways and access it you have a valid path to throw the evidence they discover out as an illegal search and seizure of your property. I'm not a lawyer but that is the general thought process on denying them access to your property.

Edit: Just want to say this mostly pretains to United States law and similar legal structures. This advice is not applicable everywhere and you should research your countries rights and legal protections.

what is the best way to refuse to do this?

try to be as white as possible.

If you reboot your phone, the first unlock can't use biometrics

Or just know how to enable lockdown mode. On iOS that’s 5 rapid clicks of the power button, screen on or off, and it vibrates to let you know you got it without looking. Dunno what it might be for android, or if it varies by model.

It ends up like a newly rebooted phone; requires a typed passcode. It also provides quick links to medical ID info and the sos emergency call thing. It may, if you have an ID set up, also have a link to that, but I don’t have that configured so not super sure.