I would call this situation a public service. A large version of a cop pulling over a white lady driving a Volvo at 3AM in the projects. "Are you lost? Just follow me, ma'am and I will take you to the freeway...". The officer had no right or reason to interfere with her travels. Did it because it was right, or saved him paperwork later, or she reminded him of his mother, whatever.
He also didn't have to seize her to see if she was lost, neither. He can blink his headlights, toot his horn, put on his hazard flashers to see if she will pull over. Or, pull ahead of her, and park with his travel lights on to see if she will stop and ask for directions. Or just follow her until she pulls into a convenience store, or pulls over on her own to use her phone for directions, etc.
Your example ranks right up there with a little PR-stunt I've come across in the media. Some city would get on a PR kick about welcoming tourists or business or whatever. So, once a week they direct the police to pull somebody over on the interstate going thru the city, and invite them stay the night or weekend in a nice hotel, meals included, compliments of the city government. Sounds great on the surface, until you realize there is no authority to
seize someone on the road just so you can invite them to stay the night just so the city government can make itself look good.
Another of my "favorites" is a trend I literally ran into a few years ago--police roadblocks to question drivers whether they had seen anything related to a recent crime in the immediate area. So, let me get this straight. The cops seize a person
involuntarily in a roadblock just so they can ask his
voluntary cooperation to answer questions? Yep. That's right. Total absurdity. Worse, I came across a court case a few years later which approved this particular nonsense.