The profits from front-running get passed on to the clients in the form of tighter spreads. If an institutional broker consistently provides bad pricing, it will be dropped. No big firm uses just one broker - the firm’s traders are always looking for a better price, whether buying or selling. This is just more populist shenanigans ginned up to extort money from the big banks for DOJ slush funds - money that will be recovered by the banks in the form of higher deposit minimums and transaction fees on the backs of small-time retail bank customers. Before these “reforms”, deposit minimums were negligible. Regulators are pricing working class people out of retail banking.