Heyer's pretty good about it; she's one of the ones that I like to read. Balogh is also fairly good about keeping her characters rooted in their reality.

I do note that the bodice-ripping Regency is gaining ground; several of the ones that I've recently read - the Dodds come to mind - have been of that ilk. It's almost sex by numbers. Sure, there was premarital sex in the Regency, there's always been premarital sex. But to lose your virginity standing up on the porch while a party goes on in the main house a few yards away? I don't think so!