Couple of comments on the current discussion here:
How many Nationals fans are you actually likely to encounter, el-pietro? I mean, you're in Ireland, right?
Presumably the same small handful of fans that followed the Expos when they were in Montreal! Most Montreal fans disdained the Expos before the move.
The A's moved to Kansas City 65 years ago, in 1954 (the year I was born). A's fans who actually remember the club in Philly are, by definition, in their mid-70s or older. Fans who weren't little kids at the time of the move would now be in their 80s. There are undoubtedly a few around... but sadly, fewer each day.
The Braves moved from Boston to Milwaukee in 1953. Same observation as with the A's - not very many fans left who would actually remember.