Because no client supports publishing with a "-" tag currently I placed a simple form there on the landing page that will do that arduous task of adding a "-" to the event before publishing it.
Discussion
Also it uses your follow list by default for deciding who can read your notes, but if you want to do a custom list you can easily achieve that by publishing a custom kind:3 follow list to Lockbox specifically (using a "-" tag so it won't get spreaded to other relays) and then Lockbox will read from that custom list.
Three whole characters. Wait, no 6! ["-"], Ardouos indeed, that landing page is a trooper!