I (Scott) just got a call today from the Port Authority stating that in the last couple of weeks bus drivers have reported cyclists starting to walk their bikes out in front of buses at stops before the bus has completely stopped. This is a good way to get run over. Tip 1: waive a bus down and then wait for it to come to a full stop. Make contact with the driver and tell him or her you will be loading your bike before stepping in front of the bus to lower the rack.
We were also told that cyclists are not alerting drivers that their bikes are on the front of the bus. Tip 2: before exiting the bus tell the driver that you have to get your bike. That will tell the driver not to drive away with your bike on the front or worse, start driving away while you take your bike off the front rack.