Boas will NOT eat as much as you give them

[John1982]

So they know if their bodies require food or not

Regardless, they don't know when their next meal is coming. A lot of snakes will gorge in the wild, given the chance. As far as they know, it could be months before their next meal. This is pretty much hardcoded into them so you're not going to change it. The thing is, these sorts of feeding opportunities are rare or at least seasonal for most. They aren't doing it all the time like when you offer massive meals every 7 days..

I am beginning to believe that you can,t overfeed any snake in normal ways

There's a fellow in my area who works with reptile leather. A lot of the stuff is roadkill salvage but he gets a fair share of dead before their time snakes from folks who think the same as your above quote.