whilst I don't like the idea of giving a child a medicine for no reason other than to sedate them, I think that using a sedative medicine should not be discounted as lazy parenting all the time. For example a child anxious of flying, phenergan might make all the difference in allowing them to cope on the flight. Or for my eldest son who recently broke his arm. When it came to choosing a pain reliever in the middle of the night I always went straight to the codeine which has a sedative effect as well as a pain relief effect, rather than ibuprofen or panadol which would merely reduce the pain. Medicines aren't always used for the sole reason they were invented. Sedatives are frequently used for anxiety, asthma drugs to calm an irritible uterus, and yes, phenergan is used sometimes for it's sedative effect when it is not needed for any other reason. If a child hasn't slept in days due to illness or teething and has gotten themselves into an cycle of being too tired to sleep it's not that much of a leap to say that phenergan might be the thing that helps break that cycle.

Giving it because you are going to the movies, however, is ridiculous no matter how a parent justifies it to themselves.