All these rumours come from the fact that easyJet is always in discussions with lots of different airports about the possibility of establishing bases there...
Prior to the MAD base being announced, other bases such as BOH were under consideration, and discussions were taking place with airport owners. I think I read in Airliner World (spotter mag, I know, but it's usually the most reliable source for info) that easyJet was in discussions with up to 30 different airports and would make a final decision on just one.
I would imagine that employees at these airports hear about the discussions taking place, assume that their airport will be the next base, and then the chinese whispers start.
This usually ends up in disappointment for those of us who built our hopes up for a NCE / PMI / AGP base!!!