Why can’t you pet working dogs?

Because it can distract the dog from doing the job it's been trainned to do.

Do you like being distracted when your hard at work trying to the best job you can? 

You shouldn't pet a Service Dog except if the proprietor gives you consent. Most don't need their canines contacted by others because of the sort of preparing the canine went through to be a Service Dog. It diverts from their preparation.

Petting grouping breeds is OK. Petting other working canines are OK, you simply don't play with a Service Dog. The canines need to remain totally centered around their proprietors. The canine could be required while you are petting it and the canine wouldn't manage its work.

It takes their mind off what they are there to do.  It is also a sign to them that it is play time, which it is not.  Just stop and think about it for five minutes!

Petting them is a big part of their training. Having many people pet them will be confusing, or in a way, retrain them to respond to anyone; not just the owner. The owner needs this training to work so the dog can do its' job. Usually, their jobs are to preserve the owners' lives or maintain a dignified quality of life, in some way. It's good for the owners and good for the community. So, leaving them alone to work is very important. Lastly, if you ask, they will all have a website they refer you to, to explain the need for service pets as well as the need to leave them be.

Working dogs cost almost half their life to be trained to do job.

To teach them how to do it, they use petting "AFFECTION" as reward. Also treats and other "good things".

If  you teach a dog he doesn't need to do  WORK  to get paid.

Guess what the dog will do?

THE DOG WILL STOP WORKING BECAUSE STRANGERS WILL PAY THEM AFFECTION EVEN IF THEY ARE NOT DOING JOB ANYMORE.

What happens to person who needs dog to warn them if they are about to get a seizure? Dog doesnt care anymore, because stranger will say "GOOD BOOOOOOYYY" while the owner is dying

YOU STUPID IDIOT

Because they should only listen to their handler.

Plus the fact, were you in his lambing field, trying to you so . Then you would highly likely get bitten, herded  and/or driven, and contained in a corner either by him or his working partner until either my arrival, or my awakening.

.... Very seriously also.

You shouldn't pet a Service Dog unless the owner gives you permission.  Most don't want their dogs touched by other people due to the kind of training the dog went through to be a Service Dog.  It distracts from their training.

Petting herding breeds is okay. Petting other working dogs are okay, you just don't mess with a Service Dog.  The dogs need to stay completely focused on their owners.  The dog could be needed while you are petting it & the dog wouldn't be doing its job.

Because they're WORKING.  Would you pet a working human?

cause they'll get distracted and wont do what theyre supposed to do