Occasional/seasonal users are rarely aware of the workings of licensing and subscriptions/tokens, but as with any consumer product, they should be MADE aware of how much they are being charged for a service.
Right now we cannot even think of implementing FLEX before Autodesk implements some control to notify users before tokens are consumed/charged, for two reasons:
1) Whenever the user launches an application, they need to know how many tokens will be charged (and possibly their cost with it);
2) Whenever an application is left running by accident, the user should be prompted their time is expiring and the application should close before charging for more tokens (imagine a seasonal user who is out on vacation but left Inventor running on his Windows user that is locked).
From the Flex license tutorial video (https://www.autodesk.ca/en/benefits/flex)

Please and thank you.