I work with a fintech company where we have had to completely block M247 IPs due to continuous attempted fraud. We generally allow access through VPNs otherwise. We are very receptive to customer feedback, but there have been no customer complaints despite having M247 blocked for months.
There was an Ask HN from 2 years ago that was also suspicious of M247 [0] -- verging on paranoia -- which provides only weak evidence, but it does not encourage us to unblock M247 anytime soon.