One b - it's short for probationer, and if it had two b's it'd have to be pronounced to rhyme with hobbies.

Meanwhile the powers that be believe that closing down firehouses and sacking firefighters in New York is a good way to deal with budget problems."What price a Hero" And they haven't had a rise in three years.

And in England the Fire Brigade Union has just resolved to ballot its members on industrial action for the first time in a generation, in a bid to get a fair wage. (And here is a downloadable petition in support of their demands.)