Even worse, the poor author has created a hacking tool capable of enabling said felony, which I believe could get them 10 or 20 years... I'm looking for the statute now.

Edit: I was mis-remembering, the current law is against possession or manufacture of eavesdropping or wiretapping devices, not hacking tools. The EU has been playing with laws against hacking tools, but apparently nothing in the US yet against it.

The law makes it illegal to distribute devices (incl. software) that the design of such [software] renders it primarily useful for the purpose of the surreptitious interception of wire, oral, or electronic communications. Punishable by not more than 5 years and/or not more than $250,000. 18 U.S.C. 2512.

I don't think this blog post qualifies as an "interception" device,... however unauthorized retrieval and recording of another's voice mail messages constitutes an "interception" so who the hell knows. I'm sure you could find a US DA who would argue the falsified User-Agent meant the software is designed to "intercept" communication meant only for Google.