I know it's happened, but the number doesn't seem to be very high. (I'm going strictly on memory and not actual numbers).
The problem with that is, most of these type of people tend to be traumas, not the chronically transfused people you see often. Once they've been discharged, we may not see them again or it may be years later.
It may sound crass, but for it to be a problem, they need to survive the event which is causing them to bleed to death. Developing an antibody (ANY antibody) is the least of their problems.