If you charge... what was the reason for leaving the old board?
You can block certain ranges of IP numbers. Might not be pc but face it, there are large portions of the world that see us as one thing, their meal ticket. Sorry that's their situation but we aren't going to change that.
How many legitimate members are here from China, India, the Phillipines, Russia. When I realized we had zero on another board those ranges were blocked, yes that may exclude the one or two legitimate posters from those regions... I never saw them and I did hold out hope and held the door open for a long time.
This board has a far narrower focus, the I codes. You can start by blocking those regions that do not use the I codes. We might call them international but the world as a whole does not know they exist nor do they use them. Effectively you could limit the board to the US and not miss a thing. If there is anyone from outside the US here, raise your hand.
Top to bottom;
207. US- Y,
94. Warsaw- N
68. US- Y
195. Switzerland- N
91. GB- N
65. US- Y
124. Melbourne- N
182. Malaysia- N
188. France- N
123. China- N
109. Germany- N
182. Malaysia- N
109. Ukraine- N
109. 169 US-LA from GB, sumthins fishy
182. Malaysia- N
72. Atlanta- Y with a flag
46. Moscow- email is test spam, pass
213. Belize- N
Wow, who did you pith off?
You can be more diplomatic, there are a number of applicants from the "free" world that might be either way (they aren't but you can hope). You can ban the obvious ones and bump some mods to admin level, pass the questionable ones off to them, let them send out a stock personal note and get a response, then decide from there. A number of the ones I said Yes to are still highly suspect, I'll give any American a try, once, you can grill them or flag them in a way only the admins and mods can see for a probationary period. Once they are known remove the flag.
If it were me, I'd block all but ARIN IP numbers and then sift through them. Don't post personally identifying info in public again and probably hide the info above. There are a few up there I'd be tempted to mail a worm back to