JMS has always been big on doing the "please, please, never ever suggest a story idea or ask about a story concept that you've come up with" due to the whole "I've had a fan on twitter mention an idea he had to my twitter and had to throw out x months of writing work because the concept was similar and then it gets ridiculous for the lawyers to be involved."
He loves to engage with fans, but he's also very aware that he can put something in a story , have it on tv and someone can pop up and do a "I mentioned this on twitter 10 years ago. It's my original idea!"