Of course they would get GrapheneOS phones but does not make user a suspect, they also carry cash rather than credit cards, but not all people with cash should be a suspect!
The mayor problem in Barcelona is being the pickpocket capital of the world and the unregistered Airbnbs! Both are relatively easy to address (in conjunction with the legislative and judicial system), but are have not been tackled for 2 decades already. And please, don't start suspecting guys with Nike sneakers and cross bags as pickpocketers now too! There are plenty, plenty of genuine methods to go after the bad guys than cheeking their phones or shoe wear... gosh, even civilians are tired of pinpointing at them to end up being completely ignored by that police!