I would provide zero stars, if it was an option.
When they have technical problems perhaps you could inform ticket holders by email, *use the email address the ticket holder got the tickets emailed to the day before*, instead of letting them drive over 20 miles to the venue to find out about these difficulties.
We were informed by the valet that this was an ongoing problem, so it didn't just crop up with the last performance.
I understand technical difficulties happen, but not even having the courtesy to email customers (whose address they obviously have) to let them know is beyond rude.
It's a good way to lose customer's business.