Please Get a Pre-Approval Before Previewing Properties!
It happens all the time. A person will call me to inquire about a property listing. I'm more than happy to offer more information and ask if they're working with an agent. If they aren't, I usually try to find out a little more about their needs and whether they are serious buyers or just looking. As a real estate professional, it does little for me to offer my time to those who aren't serious buyers because they can get a lot of free information off the internet without ever wasting an agent's time inside a property that they cannot afford or don't like.
I ask my clients to have a pre-approval before showing them a house because I want them to show me that they are serious buyers who have discussed their finances with a mortgage lender who also takes them seriously. Plus, I'll call the mortgage lender to verify the pre-approval (yes, we can check up on a potential buyer). There is nothing worse than finding a great house that is completely out of the price range and being disappointed right out of the gate. This is a tough market and only newer, inexperienced agents will have the time to spend on "just looking" buyers when "serious" buyers are seeing 30-40 homes and taking an average of 5-7 months to make an actual purchase.
So, yes, you need to have a mortgage pre-approval or proof of funds to see the house. No exceptions.