is, AFAIK, the cheapest way to "buy" the Senator card. I even heard of cases where someone employed someone else to do the airrails for him. There are, of course, plenty of other ways to "buy" the precious plastic, including running for the Bundestag.
Lastly, as mentioned before, if you happen to be in possession of a Senator card and didn't meet requalification requirements, there is a 1500 Euro offer to renew it for one year. Bad value I would say.

Jensens