I believe I understand your point, but I don't think it is paranoid to consider how such a proposed "kill" switch could be abused.

We live in an era where habeas corpus, Miranda rights, and free speech are all under fire. I've seen nebulously crafted laws abused to erode personal freedoms, and I've seen laws intended to protect freedoms rendered effectively useless through exemptions.

Many laws are acceptable in the right context; the problem is that once the law is there, the government tends to broaden the context.

So let me get this straight: the TSA will have a bunch of machines displaying pictures of naked children? Aren't there laws against that?

...Gandalf and Elrond look pointedly at Frodo...

I think a more suitable punishment would be to give the spammer a paper cut...a minor inconvenience...a tiny pain...for each spam message that was sent.