Reading an article about the footage I can't really come to any conclusion without more information. The officers found a gun and weed in the car and if the first girl was fucking around the car while your handling the suspect that's plenty of reason to throw cuffs on her. Kicking your phone over to your sister is a good way of getting her cuffed as well even if just for the duration of that encounter. Weird shit like that is going to get you detained.
What I do find odd is the one officer doesn't verbalize for shit. He just starts doing stuff and then he does more stuff.
I had a full inventory search and hand-cuff detainment recently based on the fact I had a legal knife sitting in the back seat on the floor.
You didn't see me here bitching about it. No laws were broken and I was treated like garbage last month. Next time I'm stopped the officer is going to meet a lot more resistance and questioning as to what he's doing and what his probable cause is exactly. And yep, probably going to start recording.
You should never be able to touch the trunk/hood or handcuff over a legal knife in private property (vehicle). You can ask questions about the knife and maybe examine it to see what kind of condition its in, check it for blood (I'd consider it reasonable to make sure the knife has not recently been used and eliminating that as a reason for why the knife is sitting out), whatever. Anything more is pushing it for someone with no arrest record, no priors, and inspection sticker being the only reason for the stop in the first place.
And when he cut the citation, he didn't check off inventory search. That speaks volumes.
I respect that his policing style and interpretation of policy/law ultimately helps solve crime and breaks cases-- but we have placed limits on it for a reason.
Probable cause is a reasonable belief that a person has committed or will commit a crime. For probable cause to exist, a police officer must have sufficient knowledge of facts to warrant a belief that a suspect is committing a crime. The belief must be based on factual evidence, not just on suspicion.