As of this week, individual Belgian amateurs can apply for a secondary 2+1 vanity callsign with all possible ITU-prefixes for Belgium except ON.
The regular ON prefix is reserved for normal calls and OT5x and OR5x however are reserved for club stations. Calls like OQ1A, OP2Q, OS7Z, OO0O, OT7T, etc. will soon show up in large numbers as soon as march 27th on all bands.
Primary focus is contesting but also applicable to every day DXing. So don't be confused or think of a pirate, these calls are 100% legal.