If you have a buffer, then you likely understand that it is the most dangerous piece of equipment in your shop, that can turn anything into a missile. It makes sense to do whatever possilbe to protect yourself.
Here's some quick/effective guards for a buffer. Simply use any plastic 5 gallon bucket..... use a jigsaw, or sawzall to split the bucket lengthwise..... place the halves as in the photos, and screw each down to the bench. It will catch, or at least slow way down, anything that gets away from you when buffing. Just remember that ANY TIME YOU STEP UP TO A BUFFER, it is the most dangerous machine in your shop....so treat it as such.... with respect, because as soon as you fail to respect it, it WILL make you pay.