I think just by chance, in travel and elsewhere, you meet anyone who "always dunnit like this". The only time I actually had to show any ESTA documentation was a two years ago in BKK, checking in with JL to go via NRT to LAX. They said they couldn't see the ESTA since ticket was on AA stock (?). Having my confirmation document ID easily available in the mobile, it faced a delay of a couple of minutes max.
Of my B2Bs at OTP, only once faced some problem, when the team leader at transfer check point a badge showing he was part of "Brigati Antiterroristi". He did not accept my answer that LHR was my next destination, as I just arrived from there. Excessive security check and probably communicated with gate where I was held until last second before gate closure (previously described in detail here). The other times rather swift procedures being ushered forward by surprised faces, when they realize you're going back to where you came from. There seems to be a learning curve here, and that will benefit all B2Bers.