I'd say it's the environment too, but this happens at various locations across the country consistently with multiple types of Macbooks. Also, at these same exact locations, I have no problem using bluetooth with my Android phone, further reducing the likelihood that it's the environment. Finally, all the threads about OS X bugs relating to BT/RF/WiFi problems that have been reported for years but ignored by Apple, including reports by Apple's own beta testers, are a further indication that this is an actual problem and that a lot of people are having it.
I've had issues with a non-bluetooth wireless keyboard when plugging the receiver into my laptop directly which go away when it's connected via a USB hub a little distance away, which makes me think the laptop itself is causing interference.
I do similar. I have my dock which has a USB extension cable that runs under the underside of my desk and basically sits directly underneath the mouse and keyboard. Connectivity issues vanished.