Actually they do. But that is not really important....I doubt any MT4 broker has ever successfully sued a retail trader for $15 000.
1) Negative balance protection is only with their ASIC division, which is of little consequence anyways because a) max leverage on fx is 1:30, and I think 1:10 or so for stock cfds. So the client would need to place significantly more margin capital, which reduces their total position size anyways. Or has more capital in case of a sharp move. Offshore division
doesn't have such protection.
All it can do is prevent broker from having a client owe them money using backend shenanigans.
2) negative balance protection is irrelevant, unless the alleged opposite trades were two accounts at the
same brokerage. Then Vantage could just offset the "hedge" and/or actually prove the "suspicious" activity.
Hopefully Vantage can come along and explain how they are the victims of their client's "suspicious" behavior. I'm actually beginning to appreciate the more "nuanced" methods some so-called brokers take to minimize client profits (fake price spikes, order close delays, opening ghost trades to force loss, et al).