Was thinking about this after a minor mix up yesterday - we were heading to visit my grandparents after a day in town, DH went into one shop, I was taking the kids into another and we were going to meet by tube. Couldn't find him afterwards, his phone was going straight to answer phone, so eventually I left a message to say I was going home. Thought just maybe he was on the tube platform, so went there, but no. As a last ditch, sent him a whatsapp (we don't really use it between ourselves) and he replied that he was on the tube and nearly home, but would explain when I was out!
Turned out he was only just behind us, and he saw us standing by the tube entrance, then a group of people went past and after that he couldn't see us, so thought we must have gone into the tube (we'd gone into a corner shop). Then he saw a lift had just gone, so went in, then a train was on the platform, so he couldn't see us and hopped on assuming we were on it. Why he thought I'd just go off without him I have no idea, but there you go.
We had a much worse one years ago when doing building work at our flat - the freeholders lived upstairs and were being very exacting about how we did everything and we were bending over backwards to do everything to get their permission - we had no intention of doing the knock-through we planned without their permission. Then suddenly went outright aggressive and sending us cease and desist notices to stop all building work! Eventually we abandoned the knock through as it wasn't worth the fight, but we told them we had to do the rest as the flat was uninhabitable otherwise.
Anyway, eventually, a few years later when they were still asking us to pay some money to do with the legal fees, we got together with them to talk things over. Turned out, as I had suspected, wife upstairs had come down and asked the builders when they were going to do the knockthrough, and they said 'On Thursday' or whatever... failing to add that that was only if we had the freeholder's permission!
One of the freeholders clearly thought she'd 'got us' when she told me what the builders had said, and seemed amazed when I looked her in the eye and told her that yes, I was quite sure we did tell them to start on that day - at that time we were just answering a few questions for them and we had assumed they were going to OK it once they had our reply, but we would never have done it without them approving it.
The freeholders thought they'd caught us lying and we all went through all that aggro for nothing.