Allow for restrictions on the Calendar in Forms. Restrict the user to only selecting an date/time within X days out, or prevent from selecting an time before the current date. Also, it would be useful to have an restriction on the weekdays, or times.
For example, an tech submits the User Onboarding form and you could restrict it to only onboarding within the next 2 weeks. Or someone may be able to select a time only on Monday Mornings between 8 am - 11 am.