I do use VoIP, and I "spoof" in two specific situations:
Since I got a cell phone through my work, I had my old cell phone number (which I'd had for like 7 years, and it spells my name) ported to VoIP (I keep both numbers and have separate personal/work numbers, and only carry one device). Now when you call it, it simultaneously rings the phone in my home office, and my cell. When it calls my cell, it "spoofs" the outbound call to appear as though it's coming from whoever ACTUALLY called my number, so on my cell phone the caller id shows the true caller, and not as if someone at my house is calling.
The other time I use it is as a secondary VoIP service. I only have one inbound number (DID) for my "house" number, which is tied to a specific provider. I have another provider that is setup as a secondary service, in the case I try to make a call and the first is unreachable, or rejects my call for any reason. I don't have a DID with that provider, only outgoing service. So when I place calls from that line, I "spoof" my house DID number, so it doesn't show up as blocked or some random CLID.
Unfortunately, I don't see how they can distinguish these two uses from actual malicious spoofing, but I'm not in Mississippi (or the US for that matter) so this doesn't apply to me now.