Is there a quantification for the value you are obligated to provide your company written down in your employment contract? If not, on what basis are you throwing around words like "crime" and "fraud"?
The problem arises when there's little ability for oversight, which implies a high degree of trust in the system and the mechanism for verification can't be there.
Put another way:
If someone pays you $50 to fill their tires up with air, it's Fraud if you don't do it - irrespective of your customer's ability or willingness to verify.
If your customer was busy on the phone, or with their children, would it be 'Perfect Contractually Acceptable' to not fill their tires up with air 'Because You Can?'?
Either legally or morally - no - it's fraud.
Fortunately, most tasks involve a kind of implicit oversight - i.e. 'you know when your tires were not filled'.
In software, the mechanisms for oversight aren't so great - but that should be fine with all of us to the extent that we're professionals - we don't want Management breathing down our necks anyhow. But the inherent level of trust implies a higher degree of professional competence on the part of all of us.
FYI - this is assuming that there is a problem with oversight. If the OP is doing some 'genius 2 hours a week', the company knows it, is fine paying $150K for that bit of work, that's totally fine.
It's disturbing that this is even a discussion.
Look, i’m not saying it is a valuable way of looking at productivity at all, but the fraud aspect is reasonably clear.
So if it states 40 hours, you put in 40 hours. If you do nothing during those 40 hours, we can have a moral/ethics discussion about if and how you should change the situation etc, but at that point we’re outside of the fraud scenario in my opinion.
I will say from experience that someone who does 10 hours of good, productive work a week is still adding more value to the company than someone who works 80 but writes terrible code, ships bugs and causes outages. If you want to accuse someone of fraud for not being valuable, go after the latter.
In my experience in Europe, an employment contract will state number of hours (say 36, 40, etc) and you need to be present and available for that time. These are non-hourly contracts (e.g. salary is expressed by month not hour). None of that has anything to do with productivity, to your/mine point.