A big "banned" screen will cover your RS applet.
You will receive a message in your RS Inbox about the offense
It will be recorded on your offense history in your profile
When you go to log in after receiving an offense, it will tell you and suggest you check your offense history before playing again
Mod Mark stated in the Live stream that 2nd chance macroing offenses, and perm ban offenses from BotWatch would lead to an email being sent out, HOWEVER, I believe he said there will not be any kinds of links or login redirects, etc. It will simply say your username and that you were caught botting.