I remember boarding an Embraer in YOW on a drizzly dark evening and upon seeing a field of precip spatters on the wing, asked the cabin crew if that was ice.
Shortly after I was called to the jetway to discuss with a pilot who asserted that the OAT of +3C meant it couldn't be ice. I didn't open a discussion of the physics of cold soaked wings and near freezing precip, but did point out that on my own aircraft I'd be checking with my finger.
A rampie was sent out to check the wing and determined no ice was present.
As far as I'm concerned, if there's any question, it's time to check.