Blood supplies on the hoof
While the movies may make kidnapping and assassination the primary threats in protective services, we know the actual threats are more mundane: Accidents, automobile accidents, fires, and medical emergencies. One common thread to all of these is that there may well be a need for an emergency blood supply for the person being protected.
In the U.S., where there is a generally available supply of healthy blood, this may not present a problem. When traveling overseas, however, the situation can be quite different. Because of this, it is imperative to check on whether there is a readily available supply of blood, and whether it is well-screened. Frankly, there are some areas of the world where we would be personally loath to accept for our own use blood from the local population, independent of any assurances or guarantees given to us.
There are several alternatives available. In some cases a supply of blood can be taken on the trip, although there are a number of logistical concerns involved. And we know of one occasion involving what was literally a hostile business takeover in Latin America, in which a hospital was rented for a short period, and outfitted with medical staff and supplies, including plasma, for the duration of the problem. This is obviously an unusual circumstance, mentioned here only as a curiosity.
An easier solution is to make sure one or more members of the protective team or staff shares a compatible blood type with the person being protected, is willing to be a blood donor, and is assured to be a low-risk candidate. This can, of course, be less of a problem if the principal is a universal receiver, or if the staff contains universal donors.