When I have to talk to strangers on funnytimes sillysites I try to note somewhere in my missive that they are not obligated to respond, as an attempt to be clear they don't need to feel guilty if they don't get back to me/don't want to deal with a stranger's questions/etc.
For the most part this has worked out well: either I get a reply or they don't write back at all. But someone has finally found a confusing third option: responding to my extremely specific questions with "Thanks for your interest!" and no further reply/info.
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I mean... it's not illegal and I'm not mad, I just planned on either answers or silence, not "I am acknowledging you are asking me specific questions!" and then not,,, answering them,,,, 