Russian custom w/music lessons

The piano technician came to fix my piano again. I have a very talented 8 year old and the technician is very interested in his musical education. His English isn't very good and my son doesn't speak Russian, so the tech recommended his friend, another Russian. My son takes lessons from her. Today the technician tells me that my older girls, who play violin and viola need to take piano lessons as well. (One of them I have thought about, but viola lessons, violas, and orchestra are so expensive I can't pay for piano lessons too.) Dmitry then tells me the story of Rostokovich, who is (or was) the best cello player ever. He sat through everyone else's lessons before his and so learned much more. Dmitry told me to send my girls to watch my son's lessons. I think that is not right, paying to teach two for the price of one, but Dmitry says this is the Russian way. Anyone ever hear of this before? I don't want to be rude to ask.

It's true that for most Russians it's not all about money, so do not worry about it.

Watching your son's lessons and taking lessons are a bit different, and if the girls behave it won't make too much difference to a teacher.
It very much depends on her personal attitude. If the teacher thinks that your kids are talented and are in need of extra lessons it's entirely possible that she'd love to help you out (and yes, in Russia it happens often enough).

In other words, if the teacher is ok with it you should not worry too much. You can give her a small gift at the end of the year to show your appreciation of her efforts if you wish (not money and not anything expensive, maybe a cake or a book).

But make sure first that she is willing to make adjustments and take your girls in, and it's not just Dmitry's delusions. :)

This difference between formal lessons and audited lessons exists also in other places, and other fields of study. The difference has to do partly with accreditation/prerequisite status. Formal lessons includes testing and recognized accreditation if passing tests, that will be recognized for further lessons or more advanced courses, and other teachers. Auditing lessons/attending for personal interest/improvement doesn't carry any recognized accreditation, has no tests. It is obviously worth something, but has a different status. Some kind of gifts of appreciation would seem to fill the bill, perhaps? For some kinds of auditing of lessons, payment is required.

Tatiana has told me several times to bring my kids in, but I have declined just because I have so many. She told me her 7 year old would like to play. I told Dmitry if my girls went to lessons, they'd play with Anastasia. Dmitry says, they'll learn while running about. I guess I'll let one daughter go next time and see if all goes well. Dmitry is coming to the next lesson to supervise my son's teaching. I told him he should just teach my son himself. He's so very funny. Anyway, I am teaching my children Russian, but it is slow. They cry about how the letters in cursive look different and ask why they have to learn cursive too....