Start / End time error if not entered in 24 hour clock format

If you try to publish an event and put 1pm as the start time, it lets you publish the event but sets the data and time to January 1, 1970 without a start time. Same issue for end time.

I know that a 24 hour clock time format is required, however not all authors of the site know this.

So, i'm asking that you impliment a warning function as well as a label to instruct authors that they must use a 24 hour clock format for the time. If they try to add 1pm or 1:00 or anything other that 13:00 format, show a red error message and dont allow them to publish the event.