The ploy works even though the recipient of the apology seldom gets it from the person who made it necessary in the first place.

The ploy. That says it all.

An apology from a large company means about as much as a customer service representative bidding us with affected cheeriness to "Have a great day!"

In my dealings with customers
1. Most customers deal with you in good faith
2. They will put up with your disagreeing with them as long as they think you're dealing in good faith.
3. A sincere apology works wonders..

We have "fired" customers before.. (customers can fire you as their supplier as well).. for not dealing with us in good faith.. ie making bogus claims, etc. ("Mr. ____, its evident that we just aren't a good match for your needs. I suggest you call ____ (the competitor I dislike the most) and see if they can better serve you."

It's not a "ploy" but it is good business.. and it helps to strengthen and build relationships. We're in a word of mouth world now..