I feel that one of the reasons scammers flourish is that there is still some stigma attached to finding love through a dating agency. For this reason, people are less likely to confide in friends and family and this secrecy means they don't have the benefit of an independent viewpoint on the 'ideal' scammer.
Well, I've already had one long relationship with a perfectly genuine chap I met through an online agency. That came to an end, but recently I met someone new in the same way and he is local and really, seriously nice and right for me. I know four couples who met online and are happily together after several years. There are dangers, but there are also positive aspects and there should be no stigma.