It depends what they are lying about and how it's impacting you. It's not my job to fix someone's fibbing ways. Way beyond the scope of my job. I don't quiz parents on anything either.

If someone comes and gives me a heads up that it was a rough night, or they didn't eat much breakfast or similar, it's nice information to have, but it's actually none of my damn business how their parent on their time.

The ONLY issues I address with parents is on-going behavior challenges and that's not done to complain, it's done to come up with a consistent strategy so all party's are dealing with it consistently in a way that suits but them and me. Any none child related issues with the parents (pay, drop off times, collection times) are of course deal with as they occur.