Your friend is a tad too paranoid.

Which LEO is going to be trying to harvest IP's? Federal or local? If local, what are they doing, just surfing around on the off chance that you will be in their jurisdiction, say you are and give probable cause for a warrant?

If federal, why would they give a damn unless you are showing you are growing over 99 plants and selling them?

Now, let's say that an LEO is interested (its a huge leap, but for the sake of argument)...They aren't going to get your address from the IP number. They would get your service provider, unless of course you are using a proxy and then it gets even more complicated, especially if your proxy is in another country. They would then have to subpeona your service provider (showing cause) to get your name/address.

The first amendment still counts for something and I can say anything I want on this website about who I am and what I am doing...No way to really prove it's me typing this, if you get my drift.

I've been on cannabis boards since 2002 and have yet to hear of anybody getting busted for posting to a cannabis forum. The logistics are just too complicated and time consuming for little gain for the LEO's, imho.