This is really the last reply Im giving to this discussion. Im not trying to win an argument, im just trying to give people some advise for future situations.
Try to separate the common traffic control from the 'getting pulled over and your car or clothes searched'. That has nothing to do with traffic behavior. So if they stop you and ask for your drivers license, you could ask them: Is this a traffic control?
If they bend the traffic control ...and say they want to search your car you could ask them If you are obliged to do so. In most cases you are not! Unless the mayor of the area has a temporary search order for everyone there. Sometimes this happens after violence in the area.
If it was a traffic control, then what are they searching for? If you hand them your license, you're registration...they have no ground to search your car. In some countries they have rights to see if you have a yellow vest and a danger-triangle, but that's it. So I'm sorry but I will stick to my point: There is NO stop & search law. There is a traffic law where they can stop you and do a common traffic control and sometimes they will use that traffic control to make further steps. Sometimes it's easy for them because the driver smells like weed or acts suspicious. Sometimes they will try to use scare tactics and make you think you have to comply with everything, which is understandable because you are in a foreign country. But its Spain, not Turkey or Syria. You have rights.
To actually search your car and your clothes, like they did in Benimussa and now Circoloco...they need grounds for suspicion of weapons/drugs/counterfeit/stolen goods whatever. Pulling random people out of taxi's because it's Ibiza and DC10 is full of drug users will NOT hold in court, im telling you.
There is a law term that is internationally used for this, it's called DETOURNEMENT DE POUVOIR. For law enforcement that means they are not allowed to use law/power A for goal B instead of A. Look it up.
Does my rant make the situation any different? No, they will keep doing it, so be careful out there!