It depends on what you do.
P&D drivers; City drivers at XPO have 30 minutes deducted unless you fill out a sheet requesting that it not be deducted if you work 6 hours or more.
If you want to give away your 30 minutes of time to leave 30 minutes earlier or to get some extra work done , nobody in management will object. Management wouldn't object if you purchased your own tractor with a bigger engine and no governor so you could run faster , and don't forget to pick up the tab for the fuel and insurance too!
That's an extreme example and I hope nobody goes that far to "help" their employer , but to all of the hardworking folks out there -
Stop and give yourselves a break from time to time , you earned it ( and don't give it away to get away )