If someone is going to get paid to build it anyway, I might as well be the one getting paid for it.
Where do you draw the line?
Ready to do anything for money as long as it seems legal-ish or your ass is covered by hierarchy?
Yeah, there are reasons why "someone is going to do it anyway" is a classic example of an ethically unsound argument.
This attitude is the reason “someone is going to get paid”.
If you see a unattended laptop in a coffeeshop, do you steal it because “someone will steal it, so it might as well be me”?