I'd wonder, and maybe ask, if they need help, so I'd remember them. And people who believe they're handy might come up to chat to see what's being worked on

But someone in a PPE and a clipboard? Could be a worker, could be an assistant running an errand, could be a safety inspector, could be the big boss - it's a nice mix of "that person is probably here for a reason" and "that person might be a headache with a penchant for power trips". I'm not going to approach or remember that person

Best part - if someone with a ladder or a tool belt is looking around or hanging out somewhere, they look like they're lost. If someone with a clipboard is looking around, they're probably inspecting, and if they're opening doors or looking around somewhere unexpected, they're probably just looking for a quiet place to fill out paperwork or make a call - easy excuse with no loose threads