Using a businesses own website to sell them something

I would like to make a copy or screenshot of a businesses' website, make some alterations to illustrate a service that I can provide them, then use it to try to sell them that service with a real example from copy of their own website.

It would be a private communication, not available to the public and I would only use that businesses' website to communicate with them directly.

Would this be considered fair use? Could I get in legal trouble for doing this? Do you think this would make business owners angry?

 

Yes, you can. But if you make sample so good, they might just done it by themselves.

 

I don't see how it would make a reasonable person angry.