The best approach IMO is to reply to a C&D with a response like, "We'd be quite happy to work with you to ensure there is no customer confusion. I have started by reviewing the site and trying to make this clear. Do you have any other suggestions?"
Yeap. Put the burden for remedy back to the other side. Go through the motions and hope you'll waste enough of their time, energy and money such that they may reconsider the value of their present strategy.
There is a difference between something which clearly attributes the trademark and disclaims any link and something which does not.
I have gotten unreasonable C&D letters in the past. It's a typical lawyer tactic of asking for the world and then negotiating back to a reasonable solution. I have always responded with something like that. I have never had the lawyers on the other side say that such an approach is unacceptable.
The fact is you can use a trademark refer to a trademarked product. There is no disagreement there.
