Stripping the donor.

[Hoybi]

I'm about to slaughter my 4th Sierra, 65000miles Pinto 2litre automatic. The engine will be used withoout electronics. So very much old school. Fits with the owner I guess.

A question though:
"One huge tip, remember to slacken the rear hub nuts while the car is still on it's wheels you'll come to regret it later on if you don't"

But for what reason ?

The shaft can be taken out of the hub carrier without loosening the nuts.
So I don't see the point. Won't you mess up the bearings ??