Racecafe does not have 15,000 members. BGP have marketed themselves very well on social media. There is a flaw in there approach in terms of sustainability but we will leave that for another day.
As for High School members that is a large proportion of Facebook members. BGP may have targeted that social media channel. Not hard to do.
As for the NZ domain vs .com argument the law allows it. That's one of the reasons Racefields Legislation is on a hiding to nothing. The internet is one of those few remaining places where there is freedom. Everyone competes on price. Isn't that how it should be?