@Erik That's exactly correct yes. And I appreciate that this will annoy some people but I tend to only do it to people who I know are bad at noticing notifications etc. So it gives me two chances of getting their attention.

@bharal If it takes 2 minutes for someone to context switch before they respond, you can use that time (after the first message) to type your question. If you don't then you have to wait the 2 minutes for them to change their attention AND the time it takes to type the question (bear in mind question formulation isn't just a typing task). It's a micro optimisation for sure but I work with some people who are really bad at responding (not because of being busy).