I have met Sondheim a few times - briefly - he is unfailingly gracious, a little shy and appreeciative of fans. You never want to gush but a simple "I really enjoyed SUNDAY (or whatever show)...", or "Thank you for all the wonderful shows." He also is quite happy to asnwer specific questions.
I think some people are afraid of babbling and making fools of themselves.
Last fall I interviewed Judy Kaye and she told me of meeting him years ago when she was just starting in the business. She went up to him and (her words) said: "Mr. Sondhiem I just want,..you are so...
burble, stammer, gurgle etc" - and he just smiled and said in a kind understanding way "I Know."
Cast albums are NOT "soundtracks."
Live theatre does not use a "soundtrack." If it did, it wouldn't be live theatre!
I host a weekly one-hour radio program featuring cast album selections as well as songs by cabaret, jazz and theatre artists. The program, FRONT ROW CENTRE is heard Sundays 9 to 10 am and also Saturdays from 8 to 9 am (eastern times) on www.proudfm.com