Police didn't just walk up to her and be like "Hey, gimme your ID"
They were responding to a called in complaint.
Whatever racial motivation there may or may not have been rests on the caller, not the responding officer.
Called-in complaints to the police switchboard can be about essentially anything, including stuff that most people would not see as legally offensive if it happened right under their noses - and in this age of on-the-fly communication (sms messages, cell phone calls from a hidden number or e-mails coming from a cover e-mail that has no realation to your real id, therefore untraceable back to any r/l individual, etc) it is easier than ever to make an overstated complaint. or just for the police to pretend they have a real complaint at all to act on. I think what's really troubling about this incident is if it means the cops could effectively walk straight up to anyone
, everyone and treat them as if they were criminal suspects on the scene without having to offer any premise at all on which they wanted her ID, without any expectation for the police to use their good sense (and yes, this might tie in with racial profiling, but it's wider than that).
The police could effectively cook up a complaint afterwards or act in collusion with someone they know (including journalists or real criminals). Even if they had to admit afterwards that the original complaint was inaccurate, that would not affect the right of the police to freely ask any John Blow for their ID papers and treat them as a suspected offender if the person/s didn't want to show their driving license or ID card - and there could be many reasons why one wouldn't want to show one's cards to a cop even if one is totally honest and law-abiding.
I know cops in most countries sometimes abuse their powers, and are then able to rely on a "no talking to outsiders" culture - but it's kind of worse if it's actually done within the bounds of legality, of police operational rules.