"you have no other context of what happened" - no, I only stated it briefly I do have some other limited context which I did not include. There were four police cars surrounding the car (two to the front and two to the rear) while multiple police officers were crawling in and out of the car in the front and the back doors as well as going through the trunk while the the driver was being questioned by an officer off to the side at the rear of the car. Maybe they were having a hard time finding the jack and/or spare...Federal law allows interstate transport of firearms from one place where you lawfully own them to another where you can lawfully own them.
Basically, in addition to the above provisions, the guns must be: inaccessible from the passenger compartment (or stored in a locked container), unloaded, any ammunition should be stored separately.
OK... So you saw it one time and you have no other context of what happened. And certainly no one on YouTube ever lies...or at least posts sensational type stuff for added views and $$.
How many tens (or hundreds) of thousands of people go about their business every single day transporting firearms in their car and don't get robbed by the police. For all you know the cops were helping the guy change a tire and had to leave for something else. Regardless...your initial post referenced police forcibly taking your belongings for personal enrichment. I'm thinking you have better odds of being bit by a shark in OK than having that happen.
I'm not saying that police misconduct is unheard of. But what you're worried about is likely next to non-existent.
As far as I know it's legal to transport your own private money around in your car too. Has anyone heard of a citizen having his money confiscated by the police?
Has a federal judge ever put an entire police department under a 'watch' or sort of a probation for routinely and systematically violating people's civil rights? Nah, never happens...