In heifers it varies somewhat between breeds, also. It's very much the norm with Limi's, pretty common with Angus', Chi's, Simmi's... less so with Maine's, Shorthorn's and Hereford's unless they're pretty short haired anyway. Like others have said, to me it should depend on the individual animal, but we have been scolded by judges for not slicking the necks of Limi heifers (they were blocked in nice and tight, too).
Steers, I'd say it depends, but if there's enough hair to block it in, we usually try to do that rather than slicking it off.