Maybe Seinfeld purposely did this to try to avoid paying her. Maybe he did know she was an observant Jew. Don't you think this woman would have told him (if she didn't she's an idiot) or any client since most people will look on a Saturday? And why did Seinfeld feel the urgent need to go see the place again? He couldn't have waited a day? Something isn't kosher about how this went down.
This really is worthy of a Seinfeld episode. Look for it to be covered on Curb Your Enthusiasm one day, although Larry David might want to be sure he has the rights to the idea before he does.
Or does being "well known" exempt one from knowing anything about his or her own ethnicity or religious traditions.
You know this is actually consistent with something I noticed in the ranks of management ~ the higher they went the more ignorant of the business they became, with those at the highest levels knowing the least.