I think that the main thing to keep in mind is that you don’t have control over the lives of open source maintainers. This is something that is quite unintuitive to a lot of people for some reason. A lot of people will specifically ask for help from maintainers all of the time. One of the worst things about this is that, many times people will seek out the maintainer of the library for questions which don’t require the maintainer at all (“how do views in Julia work?” in a private message, vaguely linking back to something said in package docs), which discourages others from answering simple questions and puts more burden on one person. But you have to remember, an open source maintainer is not your private support team! They have the ability to make decisions on my own whether your post/problem is worthy of my problem or time. If they choose to not respond to you, that sucks but it’s their call. (If you really want them to respond, offer them money or a paid vacation 
). Remember open source maintenance is donating time.
Pinging a maintainer is you making the public determination of what is worthy of their time. It’s you taking the initiative and saying that they should respond. That’s fine, but you better be right 
@Tamas_Papp gives a few rules that make it easy to be right:
Another thing to note is that different people have different tolerances to being randomly pinged. If you don’t know that about them, then you probably just shouldn’t do it.
BTW, I don’t know if everyone caught it but @mohamed82008 won this thread.