In the past, the guys who gave out their handles and had problems were the ones who were either assholes or had an agenda of seeking discounts or special favors. Eventually, no matter what name or handle you are using, if you are an asshole, you are an asshole under any name, and if you are a favor seeker, you are a favor seeker under any name. So in the big picture it is irrelevant. The agency owners figure out who the problem clients and discount seekers and trouble makers are, no matter what they call themselves.
For those who are not assholes and are not seeking discounts, the main issue in giving out your handle is a loss of anonymity and what that usually means is if you post a bad or critical review, the agency will know who you are. And with some bad reviews I read, a lot of the issues that are raised are issues that could be privately discussed with the agency and then worked out. Other bad reviews have agendas behind them, pursuant to which the poster sought special service and did not get it, making the resulting post arguably board terrorism. Of course, some bad reviews are legit honest bad reviews, and it is these posters who most need to fear some kind of retaliation.
Many of the posts here assume agencies are completely ignorant of who they are dealing with if handles are not used in the booking process, and this is an absolutely false assumption. In the past there were bad apples who became known bad apples under one handle, switched handles and guess what, they were still bad apples under the next handle. People just are not that stupid. The girls know what guys look like, they know who has a birthmark on their cock and the agency owners, some of them anyway, have amazing voice recognition skills. I would go a full year between calls to Chris at Devilish and call him from a new number and he knew exactly who I was before I introduced myself. He has amazing voice recognition skills. Although my voice is distinctive, it is not THAT distinctive.
There is also the issue of handle impersonation, and it has happened on more than one occasion that people have claimed to be a poster under a certain handle, that really isn't. This is the Internet and anyone can claim they are anyone. This tactic usually does not work for reasons noted above. But guess which people are the easiest targets of handle impersonation? The ones who are totally unknown. If you have been to the GTs etc. in the past, introductions were by handles and not names, so the people in the biz mostly know who the players are. I think Sol Tree Nutz will now be a target for the impersonators. A lot of wiseasses are out there reading his post.
Finally, a lot of posters put too many details in their reviews enabling the girl and the agency to figure out who they are. This is again from assuming that they are dealing with ignoramuses who did not notice something that they did in fact notice.