E-mail from google about robots.txt?

I got this e-mail apparently from "google" this morning just wondered if anyone has had one before or am I right in thinking it is all a big scam, cheers:
Hello,

Thank you for participating in Google Product Search. It has come to our attention that a robots.txt file is preventing us from crawling some or all of the images on your site. In order for us to access and display the images you provide in your product listings, we'd like you to modify your robots.txt file to allow user-agent 'googlebot' to crawl your site.
Failure for Google to access your images may affect the visibility of your items on Google Product Search and Product Ad results.

To ensure the 'googlebot' is not being blocked, please add the following two lines of text to the end of your robots.txt file:

User-agent: googlebot
Disallow:

For more information on robots.txt files, please visit http://www.robotstxt.org. If you have any questions, please contact your webmaster directly.

Sincerely,

The Google Product Search Team

© 2011 Google Inc. 1600 Amphitheatre Parkway, Mountain View, CA 94043

You have received this mandatory email service announcement to update you about important changes to your Google Product Search product or account

 

Well if you can allow the google boot to crawl your images and there are no secrete and sensitive images then you can allow the crawler to crawl them, you can change your robot.txt for sure. And I am not sure that google send these kind of emails personally.

 

I also received this email. There is no reason to allow Google to crawl your image directory if you are already giving them the url via a feed. I think this is just an attempt by google to harvest more image results.

 

I think I will air on the side of caution and not include the code in my robot file google has enough images on the topic I cover on my websites I don't think an additional one will make much of a difference thanks for your input on this much appreciated.