I'd always be a little worried about lifting by the scruff w/out supporting the rear, on an adult dog, regardless of breed, and even if the dog is relaxed and used to it. Just seems like bones (read vertebrae/discs, etc) are more, errrrr....set/calcified/solidified, and increase risk of injury from an unanticipated twist or something.....
Just would not be something I would ever be comfortable with, and would never want my dog "handled" that way.
Front legs...no way, not ever.
I see the Sibes drag and yank each other all over the yard (in play) by the scruff of each other's necks...and even tho they are rather young (3 to 5 yrs) it still gives me the shivers even tho their rears are on the ground and front ends are braced. I usually intercede (by grabbing the offender by the scruff, lol!) and tell them to knock it off.
Often it's not what you say, but how you say it.