Even though I was salaried, failing to have 40 hours on my timesheet each week would result in a proportional reduction in pay (there was no increase in pay if I went over 40). I mentioned this to higher ups and was told that it wasn't actually a timesheet, it was so they could determine "resource allocation", which sounded like an flimsy excuse. Using it to track PTO seems reasonable. Using it to track hours at my computer doesn't.
This wasn't a small inexperienced company. Its roots go back to the 1940s and it had over 20,000 employees, so they probably knew the relevant labor laws and either were allowed to do this or thought they'd never get called on it. Either way, exempt doesn't seem to mean much anymore other than another way for employers to squeeze employees harder.
On the whole I've been deeply fortunate to work only for companies that expect 40 hours a week. Maybe it's my field -- data science -- but either way I hope it continues. I'd do my part to make sure it does, if I knew what my part consisted of.