This would save so much hassle - In a busy environment, and due to the multi-step process to save a new service item before selecting and continuing we often find jobs booked in with no service item saved and therefor a blank. This then makes tracking down whose skis or snowboard (in our case) the job is for.
This could easily be avoided if the service item field when creating a workshop job was mandatory before exiting that panel to conitnue building the workshop job.
As labelling what the item is musust be neccasary for most users, I feel this would be a really useful failsafe and in the event it isnt required an na could be entered.