There is the possibility that Ryanair somehow had advance notice that EasyJet would announce plans at Basel on Wednesday and act accordingly on Tuesday to gain at least some sort of publicity.
If you mean publicity with respect to still operating routes from BSL in competition, then why would they make clear their intention to withdraw their services from there? Would they really announce to the world that they are withdrawing, denouncing it as a 'high cost airport', and annoy all their customers in the process etc. if they still had an agreement with BSL that some services would operate, and it was merely a publicity stunt? Strange thing to do - say "sorry, we're leaving" and then turn round and say "actually we're back again". It wouldn't encourage me to book with them.
From a conversation I had today at the airport, it seems that those in the know at Basel ATC also are under the impression that Ryanair are leaving.