I've never been a big fan of them. IMO it kinda looks unprofessional and you guys just shouldn't do it in the first place. If people don't want to follow the rules, warn them, suspend them, or even permaban them, but the reminders do nothing but clog up the announcements forum with stuff that isn't of particular value (we have the rules already, so...). If people don't want to listen then just deal with them appropriately, I'm sure you have all learned that it is literally impossible to get the message to the stupid people on the internet (aka all the idiots who need the reminder).
Just a thought.