Have you seen Access Record Locks Template? I use a modified version of this on my main database to see who has a record locked, you could also program in the auto-save, you could also have a force save (I have this to press alongside a force shutdown). Basically a table with yes/no that a timer event is checking for, when I push a button it turns to yes, users access sees that it needs to save and shutdown for an update, will warn the user it's happening and then it saves and closes.

Send in the goons with baseball bats?  Waterboarding?  How about pulling out their fingernails with pliers?

LOL
It seems like there is always "THAT" worker that can't keep focused.  I agree it is a dilemma.  Unfortunately there isn't a "one size fits all" solution.

First it seems that it is a Personnel / HR / Manager issue.  Those people / persons need counseling on the importance of leaving a record open and locked.  Interrupting others work, possible corruption of records, whatever.
  
Next, you have to decide whether to save a partial record or discard it.  Maybe if said people have to redo work they have already done they will start finishing what they started.  Richard says that no data is better than bad data so you have to decide what is complete enough to save vs not enough to worry about so discard it.

My problem has been it is usually my manager that is the guilty party.  They get on the phone and get distracted and before you know it...

You could always set up an inactivity Reminder Popup with Playing Sound.
Then again what if they leave their desk and leave the record open and computer unattended?

Lots of things to think about, but truly, only you can decide what the proper method is.  
Either way I would Track Log On AND possibly Track Changes to document the issue for escalation of the issue.  It would also give you a method of recovering critical data that you didn't save.

In my old job I used unbound forms.  If you must use bound forms, I would use a form's Timer event to set a time limit, after which the code below would run to undo unsaved changes:

Me.Undo

Another thing to consider is whether this kind of thing could be prevented at the business end of things.  For instance, data entry can be restricted to certain users, at certain hours, things of that nature.  A company's business rules and policies would decide those.