@ sitecreations: I hear ya. I don't think we are using unnecessary keywords but we may be sending too many queries regardless.

FYI, over at WebMasterWorld GoogleGuy actually replies to someone else experiencing this same problem,

"That page originally started because when someone has a virus or a trojaned machine, they often don't realize that their machine may be sending queries to Google without them asking. :)

Recently, we've started to improve the software, and it can also detect lots of things like rank checking and other automatic queries to Google. Of course, we don't show the message to everybody that comes onto our radar, but our new software looks pretty good at detecting programmatic queries. If you're using WebPosition or other software that sends queries to Google from a program, I'm not surprised if you're going over a threshold where your queries are on the radar.

If you do see this message, I would recommend not sending so many queries to Google--the volume or type of queries are unusual enough that it's attracting greater scrutiny from us. If you avoid sending queries to Google from a program, you'll be as right as rain."
- http://www.webmasterworld.com/forum30/28417.htm