[C210N]

The article is sorely lacking information...

Was the mowing deck engaged? What was the grass-level setting?

Was he mulching or bagging?

Seriously, though, a DUI arrest is reaching. Without plates and registration, cops have no jurisdiction over a non-plated lawnmower. DUI arrests are normally justified for “drivers” of “motor vehicles”, where the state has possession of the Motor Vehicle/Manufacturers Statement of Origin (and thus jurisdiction over plated vehicles).

The state lacks jurisdiction over people traveling public roads.

[C210N]

There WOULD be cause for cops arresting him for public intoxication. But, the “D” of DUI is Driving, which he was not doing.

[Bernard]

The excerpt says he refused to take a field sobriety test. Would that require an automatic arrest on DUI charges?

[real saxophonist]

Way back in college, my roommate was pulled over for running a red light on a bicycle. He ended up getting arrested for DUI.

The next day I had to go pick him up from jail, it cost 60 bucks to get his bike back from Impound. More than it was worth.

The DUI got dropped, but he had to pay the ticket for running the red light.