My House Has Turned Into a Dog Hotel!

We have spent the last five days with a four-legged guest. Now, we already have four dogs so it's not like we're hurting for canine companionship. We're already very skilled with the pooper scooper. In short, we don't need anymore dogs in our house.
It appears, though, that my wife is easy pickings for the dog owners at her work. It seems that everybody's dog can't/won't/shouldn't stay at a kennel or boarding facility. They should stay at my house. Why is it that everybody thinks if you have a lot of dogs
you would not mind having another one? Friends and co-workers seem to have no problem asking if we could watch their pet when they're away. It also appears they realize that my partner is a soft touch, that if they give her
a sad story about how the dog would not be happy in a "cage," or they would not be happy worrying about the dog in a cage, that she will offer our house. And guess what, it works!
We have had the big black Lab who tinkles in the house incessantly to mark his territory, and humps uncontrollably for no reason. We have had the greyhound who may bite without warning if you pet him the wrong way.And, finally, we have had the cute 70-pound puppy who ate my dead grandmother's desk. How cute.
My wife seems to forget that people I know (I am in the pet business)get between $40 and $60 a night for keeping dogs in their homes. That this is a legitimate business for which people are paid real cash money. Of course, my wife wouldn't dream of charging her co-workers. And friends, well, we couldn't charge them either. So, in lieu of payment, so far we've received such tokens of thanks as: old Easter candy (in November), plates and plates of cookies (some stale), home-grown tomatoes, and store-bought peaches.
I can't wait to see what the next dog brings, and I know there will be another. Maybe a cake.