if you have the devices prior to assigning them to users, then you can activate them using the 'pump station' method (BlackBerry Manager remote installation; or directly to the BES via USB).
but if you're asking what i think you're asking, the ultimate answer is no. if the devices go to the users directly, they will have to interact with the handheld (or, as within my corporation, we have desktop support personnel make a trip over to the user to activate the handhelds).
In the beginning the Universe was created. This has made a lot of people very angry and is widely regarded as a bad move.