My son is a freshman on the cross country team. He needs to do running on his own over the weekend (which, of course, means running with dad). Time got away from us and the sun was setting on our weekend. We decided to go to the middle school where they have coin-operated lights on the tennis courts.
The courts were full and the lights on when we got there, but half way through our run the courts emptied and the lights went out.
No problem. I had plenty of quarters. I started feeding the machine and pushing the button. Nothing happened. I fed more quarters, still nothing. I used the light from my phone to find a sign. No sign. A couple of walkers came by and asked if we needed help. They had a flashlight. No sign. No info. They thought it was one hour for 50 cents, but there was nothing to tell us that.
Three dollars and fifty cents later we left the dark courts for the partially lit parking lot to continue our run.
Five minutes later the lights at the tennis courts came on. Time delay? I don't know. They were on and probably going to stay on for quite some time - three dollars and fifty cents worth of time!
I owe an apology to all the residents nearby for the next seven hours of bright lights. I'm only as good as the info I am given.
So are your customers. Make sure they know exactly how to do anything and everything you want them to do. Give them signs. Give them info. Give them clear instructions. They'll be happy because they accomplished what they wanted to do. You'll be happy because they are happy. (And the neighbors will be happy because the lights will go off at a decent hour - sorry 'bout that.)
PS Our puppy didn't mind running in the dark. Then again, unlike your customer, she doesn't read signs. Your customer will get the info she needs somewhere. Might as well be from you.