What to ask when interviewing a dog walker

Good answers.
Also: what sort of management and training philosophy do they have (dogwalkers should ONLY be using negative punishment ie: loss of fun priveleges for the dog when the dog acts out). I am a pro dogwalker..and I have seen walkers alpha roll, hit and scream at dogs that are in their care. I have also seen them slap an electronic collar on a dog without permission from the owner....
If the dogs are going off leash, is it only in fenced in areas?
What is the plan and responsibility of dog owner AND dogwalker if the dog is injured or lost.

Trust is important..blind trust is not wise.

As a potential client:
Leave a leash and regular collar WITH ID for him/her to use..and not a flexi lead.
Make sure they have your veterinary information AND a cellphone number for you in case of emergency.
If your dog has ANY quirks (doesn't like black dogs, resource guards toys/sticks, jumps on people in certain situations etc)..let them know, so they can manage the environs best they can to provide good behaviour and safety with your dog.
Pay the walker on time (ie don't forget to pay on the "payday")
Provide a towel, brush and extra bags and a notebook for notes near the door where the dog is picked up/dropped off.
Show them where your cleaning supplies are kept incase they walk in to get the dog and the dog has had an accident or made a mess.
Give lots of notice if cancelling if possible.
Tip them at Christmas.

A good walker is worth their weight in gold.

And I would add...once your dog is used to the walking routine, I would check in one day and see how your dog is with the walker. Is he excited? Does he hide in his crate and not want to come out? That would tell me a lot. My dog goes NUTS for her dog walker, absolutely loves him, and I feel much better leaving my pup knowing that.

Also...not to be paranoid...but you can also check the court records for your city and see if this person/business has had any lawsuits (or criminal cases) against them. The public records are usually available online.

Actually, that reminds me of something else...you should ask if the person you're meeting with is the person who will be actually walking your dog, or if it could be someone else. If it's a business with many people, you should try to meet with the actual person.

And also, I would ask how they protect your house keys. You don't want someone who leaves that stuff laying around in their car or whatever.

And ask if they have their own dogs. The answer might be illuminating.

Also: are they members of any professional associations? Believe it or not, professional associations for dog walkers exist. And ask how much notice they need for cancellation or for an extra walk.