No. Other users will not receive any warning or notifications when you block them (the same goes when you unblock them) You will just appear as "offline" in their contact list. Yet, there is one but very unpopular menthod to check if you were blocked by a certain user.
something to do with voicemail, can't remember the exact details but a certain superuser here in this forum claims that it works.
This so-called workaround is more like a doesn't-quite-workaround.
Blocking a contact DOES NOT simply cause you to appear as "offline" at their end -- at least not in Skype Version 18.104.22.1682 for Mac. I have tested this by blocking my wife (only for the sake of science!). On her Skype, my status now displays as a cloud icon with a question mark. When I click on my status, it says, "Pending contact request." "Hmmm," I can imagine her thinking, "something fishy's going on here."
It would be great if Skype could add an option to define one's online status for specific contacts. We've all made the mistake of adding someone who later turns into a Skype pest. You don't want to hurt this person's feelings, but you can no longer deal with their endless interruptions.
Skype - please add this functionality! You will make the world a less socially awkward place.
Yes, people definitely know. I blocked someone once when I wanted a break from them for a day, and when I unblocked them they were asking awkward questions about me going "pending contact request" on their list as if I'd removed them.
I tried this with a secondary account and can confirm it.
The problem is I have someone on my list who is nice and who I don't want to hurt the feelings of, but who pounces me the second I log on and wants my attention for every waking hour until I log off. I just wish I could be invisble to him sometimes so I can pop on and say hello to a few others. Right now I have to stay invisible all the time, which is only practical if the other person you want to talk to doesn't have the same problem.
I recently just tried it myself and it totally works!
If you try it yourself, but DON'T REMOVE them from your contacts, it will show as offline
Try it out and see if it works. Cause I just hit the block, but didn't delete them. Which I thought if I deleted them off my contacts it would appear the "?"