Rest assured you will not go to jail for participating in arbitrage. You might, however, get banned from Google (Illegal vs Against TOS). This is of course assuming you are driving traffic to your MFA sites.
Ohhh of course. But I mean - you will get in trouble. And is it against the rules? is it because of the same ip address rule?
No, it's not illegal or considered causing trouble, unless the only purpose of the site you're sending traffic to is adsense. In other words, unless the site is a real site that serves a real purpose to people, it's ok. Don't send traffic to sites designed solely for adsense.
I think adsense arbitrage is dead. A bunch of people made thousands when the adwords loophole existed but those people have either had their accounts terminated (for invalid 'business model') or cannot pull it off anymore because of adwords' new quality score system. However, if you can drive traffic to your website via some other paid means (apart from adwords) and still make a profit, I don't imagine there'd be a problem with it unless you were running one of those MFA (do they still exist?) sites. Google doesn't like those. Having said that, I'd rather focus all of my energy on building a quality website with content or services that people will like and want to link to. You'll have a better shot at long-term success.