Yeah. Pre-consolodation, it was unusual, but it's not as big a goof as it would seem these days. In San Diego, I began noticing KNBC promos running on KNSD late nights during SNL and also on Sundays. It turns out that both stations are run out of LA now (both are O and O's, and I guess KNSD has no local staff other than the News studio in Downtown).
But I can also comment first hand that it happens here in Lubbock a lot. When I worked at KLBK/KAMC as an MCO, the two mastercontrol rooms are separated by a sliding glass door, so it's really just one room, with two computer playlists running off the same server. At one time, the logos and promos were very similar, with simlar numbers (different series of numbers seperate the different stations and promos now). It was not unusual for an "ABC28" promo to appear on "CBS13's" programming, but it was usually a mistake. In those cases it was because PSA had a tag on it from one station (the wrong one). So it doesn't happen as much with the Nexstar duopoly.
On the other hand, the RAMAR stations control Fox, CW, and MyTV here in Lubbock and they have no probem cross promoting any of the three stations on each other. So, you routinely see Fox34 promos running on CW Lubbock (22) and MyLubbockTV (14), and any other vice versa combo you can think of.
Of course, any time you hav a station change logos or identifiers, it could take weeks and even months before all the old logos are gone. We have had that problem here in Lubbock too, back when we swithed "NewsCenter13" to "CBS13." I had the News Director running into Master Control several times when an old undeleted promo ran.