Strong second on that!
An early interaction I had here involved a player I was chatting with in the Park quite reasonably calling it a night due to another player* acting disruptively. When I mailed them to say I had fun and hoped to see them more, I got the “doesn’t exist” message, and my heart went through the floor, thinking they were so disgusted with the disruption that they self-deleted. Which, happily, wasn’t the case at all.
I also remedied this just like Windchaser did, experimentally pinging folks that I knew still existed but weren’t online. Whew! So, I hadn’t thought about it since then. But, yes, totally worth some attention.
* To whomever is reading this: it wasn’t you.