The second one is maybe a little flippant, but it made me grin and it almost impossible to take offense at. The first sounded too clinical for my taste, too much as if the organisers didn't really want me there. It *is*, to the cold clinical eye, perfectly adequate, but my initial reaction would have been unfavorable, whereas the second would create a guilty blush of the 'OMG, did I pay my bill' variety.