My dog pees on peoples feet! HELP!!

Question
We have a female year old, unspayed, lab-shepherd mix.  She's very well trained not to pee in the house, and only does it when left along too long.  Our issue is that whenever she sees someone she doesn't know or hasn't seen in a long time, she sits on their feet and pees!  This is incredibly embarrassing for us, and confusing for her.  I would like to know why she aims for peoples feet and any suggestions for how to correct this behavior.  Help, please!

Answer
Saying why a dog does something is speculative.  With her doing it to people she knows, but hasn't seen, I lean to submission over dominance.  Fortunately, both respond to much the same training.  Spay her.  I can't think any reason not to.  Yesterday I had a question from somebody whose mixed breed was impregnated by a dog that climbed over their 6' fence.  Do you really want to put up with closely guarding her, the mess, the flaky behavior, the risks, etc. several months out of the year for the next 10-15 years? Once a female succeeds in an unexpected effort to get loose, far worse things can happen than getting bred and having a litter of unneeded pups.  

Many dogs eventually outgrow submissive wetting, but you can reduce it by building the dog's confidence up.  Start with obedience training.  The key to most behavior problems is approaching things using the dog's natural instincts.  Dogs see all the people and dogs in the household as a pack with each having their own rank in the pack and a top dog.  Life is much easier if the 2 legged pack members outrank the 4 legged ones.  You can learn to play the role of top dog by reading some books or going to a good obedience class. A good obedience class or book is about you being top dog, not about rewarding standard commands with a treat. Start at http://www.dogsbestfriend.com/  As you praise the dog for following your commands, it will build its confidence.  If the problem is from dominance, it will only get worse as she matures.  You may want to see http://www.dogbreedinfo.com./topdogrules.htm

Play tug of war with the dog and lose.  However at the end of the game, take the rope or toy and put it up, less the dog becomes confused about who is top dog.  Ropes from the pets' store quickly turn to hazardous shreds.   Ones I made  lasted much better.   Go to a hardware or home center that sells rope by the foot.  Buy 2' of 3/4" poly rope. Melt the ends, and tie  knots in it.   Get them as tight as possible, put it in a vise and pound it with a hammer.  Watch carefully, and be ready to discard when it comes apart.

Finally, make sure it has a den to live in.  If you are not using a crate, buy one.  The dog may be happier in its den than loose in the house.  It relaxes, it feels safe in its den.  It rests, the body slows down reducing the need for water and relieving its self.  Dogs that have been crated all along do very well.  Many of them will rest in their crates even when the door is open.  I think the plastic ones give the dog more of a safe, enclosed den feeling.  Metal ones can be put in a corner or covered with something the dog can't pull in and chew.  Select a crate just big enough for the full grown dog to stretch out in.

A dog that has not been crated since it was little, may take some work.
Start out just putting its toys and treats in the crate.  Praise it for going
in.  Feed it in the crate.  This is also an easy way to maintain order at
feeding time for more than one dog.