Placing the microwave ovens back from the edge of the counter top, such that the doors don't hang out into space should help with (unintentional) abuse.
Believe it or not, placing a high frequency ferrite core on the power cord close to the back of the oven can also help limit leakage on a poorly designed, older unit. Compliance engineers should have found this, but this still happens.
The best thing to do is to only buy top quality devices to begin with. Cheap ovens tend to have cheap hinges, and latches.
Is this a small medical facility? I've found that busy nurse-types are often in a rush, and can be rough on oven doors and therefore the seals.
There are both low and high cost microwave oven leakage detectors. I got mine at Radioshack several years ago for ~$11, and passing it next to the door seal will definitely pinpoint leaking seals. Any leakage at all when its new, is an indication of a poorly made unit and it should be returned immediately.