It's why i don't use hashgacha for wine dinners.
I've had a mashgiach go crazy about non mevushal wine
@jj10O0 was there.
We did a dinner in a private house and the mashgiach made the chef crazy in his face all evening.
Neemanus is critical. But controlling the establishment is not realistic. Maybe 100 year's ago in the alte heim it was.
In general I avoid frum Jews as much as possible, just lifetime of trauma of people harassing me for how I dress, books I read etc .
On the other hand, eida chareudit badatz I'd expect to be strict.