People should give feedback to channel owners that overuse announcements. 

Send a DC. Tag them in cast.

Co-create the community you want it to be.

And if they are not receptive, leave / unfollow / create a new one.

Stop thinking of channels as canonical topics.

do I understand correctly that it sends an announcement notification every time someone pins something to a channel?

if yes, that could limit the functional useability of the pin function on channels where a community wants to highlight things from community members regularly

if yes, maybe make a checkbox when pinning asking if the person wants to send a notification, and warning that it might piss ppl off lol?

thanks for clarifying

then, yes, folks should use that checkbox with caution