in the app that i wrote before, it was meant as a sort of cheap-thrill. walk into a room and turn on the bluejacking module and enjoy. so yeah, some people would get pissed.

it's easy to write. just do the usual bt scan for devices, get the list of mac addresses, query for services, if obex receive is available, do an obex send. repeat. you can implement your own cache of devices found before to speed up the "query for services" part.