It most certainly could have been used for a promo (albeit not likely.) It was more likely to be used for a trouble slide due to a technical problem, or a brief use say, coming out of a special report, or a preemption notice, like, "Due to the following special program, so and so will not be seen."
/That wouldn't be very likely for a daytime program, but, I suppose it could have happened.
//Must resist urge to look it up.....