Unfortunately, it only takes one bad apple to spoil the bunch. Reports like the one above remind me why it's so important to establish and build relationships with key media as far in advance as possible. Being transparent about who you are representing and being available to the media as a resource (not just a source) for stories is crucial. The media may not cover my clients every time, but I'm flattered when they ask me if I know someone who can help them with a story they are working on or point them to a colleague who may be able to help.
I have argued for Better Rules of Engagement when it comes to media relations. This means doing all you can to build relationships with all media before pitching. I look at it this way: cold pitching the media (just making a list based upon a database or minimal research) is tantamount to running up to someone and explaining a solution to a problem that they nothing about or may not care about. Be transparent, be a resource and introduce yourself (as much as possible) before representing clients. Most importantly, if a member of the media asks that you remove them from future communications - YOU DO IT and QUICKLY. Sending a quick note to let them know you have done so, as well as an apology can go along way and not burn a bridge.
Remember: media relations is person-to-person communications. YOUR own reputation is at stake. So, research, craft relevant pitches and then be responsive to who you are pitching - even if the result is they don't want future communications about your client.