I was looking for an answer (or a work around) for a shortcoming with time tracking and came across this gem:
When asked if it was possible to make time tracking mandatory, this was the response:
We have recently deployed Closure Rules which will help you to mandate time entries upon ticket closure.
By implementing closure rules, a service agent will not be able to resolve or close a ticket under the following conditions:
Without adding a time entry.
Without closing all the associated tasks.
Without resolving/closing all the associated child tickets.
For more information, please check out this help article.