Acquiring property from anyone about 60 years of age or older will, IMHO, increase your chance of exposure to a relative who, believing their future inheritance has been compromised, be quick to try and unwind your deal if you are not careful, citing elder abuse.

Once you hire them as your Buyer Agent, they now owe you several fiduciary duties, including loyalty (meaning they have to keep your best interests above their own and others whom they don't represent), confidentiality (they can't tell a seller or seller's agent anything about you that would compromise your negotiating position), and disclosure (meaning if they know anything about a seller or a property that could help you, they must tell you). 

If your email is compromised, you could have an obligation to report to all of your prior applicants that their information may be at risk. 

Seek to understand and negotiate a compromised solution.Suggest he set-up "auto pay" with his bank.

@Charles Hetrick it is better to stay vacant a little longer than place the wrong tenant so make sure you do not compromise on 1 and 2. 3 you can compromise a bit on and it won't be the end of the world. 1 and 2 will leave you very unhappy if you do

You do your numbers and establish the price that yields the numbers you're looking for, and then Do Not compromise.

So that the properties that the prospective buyer is looking at is pretty serious vs the ones that are just kicking the tire.As for what happened to the OP, I think both should try to compromise on a fair price for the contractor's time.  

Unless money is no-issue (and it always is) buying a house is a game of compromises, and it helps to have a clear idea of what features are must-haves and what are nice-to-haves.Depending on your response me and my team would love to help you, or refer you to another agent that is best suited for your goals.

To geek out a bit, I believe the block chain data is secure by its distributed nature, however access to it from the Client, (purse) will be compromised.  

Set yourself a cash flow objective and don't compromise.