I'm using the Events+ plugin.
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 the 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 implement 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 1 pm or 1:00 or anything other than 13:00 format, show a red error message and don't allow them to publish the event.