Soliciting audience reactions can't hurt. But I see some potential pitfalls:
- Ballot-stuffing, because the survey software doesn't block multiple responses from the same IP address.
- Survey-design issues. Some people are going to read "Would you like to have him/her conduct the Orchestra again" to mean "Do you want this person to be the next Music Director?" They're not the same question.
- Complaints from people who feel like their opinions weren't taken seriously.
- Audience variability, in knowledge, musical preferences, and listening ability. Should a candidate be marked down because too many people don't like his or her programming choice?