I was trying to come up with a scenario that would support a reasonable belief. Obviously, the meter man can’t be outside in his uniform reading the meter and convincingly claim that he has authority to consent to a search. What’s needed is meter man pretending to be someone else or having other indicia of authority such that no further inquiry is required (maybe he’s got a key, for starters). In other words we aren’t talking about just any meter reader.
I’m not sure meters are outside everywhere. They weren’t always so. For example, in Howard County Maryland,
At the end of my post, I discussed the possibility of an outside meter.
The cases don’t seem to be concerned about whether the person has actual authority. They seem focused on the understanding of the person’s authority and whether the conclusion was reasonable based on what the officer knew at the time the consent was given. That’s because that’s the test for apparent authority: