This has been happening for a while. At least since the restart. I am also a 1 and I can see there is a 4 (or maybe 6!) table for an upcoming cruise but it won’t let me book it. I’m sure they would allow it onboard if no one else wants it.I've never known them to do this on previous cruises though. They always let you just book. I get the idea I just don't think its fair for those people that are travelling solo so therefore could miss out completely even though there is availability.