QuietTiger has summed it up perfectly, Kate.
Am unwell and not "with it" so unable to add much but want to ask you this:
What happens to the dog when your nice, kind friends can't keep him?
What will they do if they lost their home, they couldn't afford him or, heaven forbid, he were to bite them?
What if they feel they have no option but to take him to the vet to be killed?
Can you guarantee that you will have him back, if necessary for the rest of his life, whether 10 weeks after you gave him to your friend, or 10 years? Of course you can't! Otherwise you wouldn't be rehoming him in the first place.
A reputable rescue will ensure under contract that any dog they rehome must be returned to them and not sold or given away, no matter how many years have passed since he was adopted. And a decent rescue will care for him until he is homed a second time or they will provide him with lifelong sanctuary.
People often think it's okay, if my pal can't keep him then she can take him to rescue... jesus if it were only that easy. QuietTiger will tell you how hard it is for us to secure places in decent, responsible rescues and we have all the contacts. The older the dog, the more "undesirable" the breed, the larger the dog, the harder it is by far to place him, even for us. The unneutered and/or unvaxed dog, the ill dog, the biter... poor little sods wouldn't stand much chance of getting a rescue place with only the help of the owner. The idea that many have, that you can just turn up at the gates of rescue with your unwanted dog and that there will be a place waiting for him is a total fallacy and one which has cost many a dog his life.
QuietTiger said:
"3) Your loved family pet was dumped and is now on 7 day death row in a pound because the new owners got fed up. (It has happened, I have pulled dogs from pounds who had the previous owners microchips and when contacted said "oh i rehomed it to blah, we don't want it..")"
That rings a chilling, painful bell.
If I had a pound for every time I've pulled dogs from pounds whose previous owners have said that I'd have a damn site more money to provide to rescue, that's for sure.