>Every ISP has to pay Hurricane Electric for their tunnels, that's why it's free to you.
Is there a law mandating this?
Is there a law mandating this?
I forgot one detail: your ISP could pay a different tier-1 ISP, as they all interconnect. Nonetheless, your ISP pays top rates for that traffic - tier-1 routes are usually last-resort routes.
Obviously if the ISP is buying transit from HE, they'd have to pay for it, but it'd be surprising if HE was strongarming their customers by adding a clause that's like "oh also, if any of your customers use our ipv6 tunnel, we'll charge you $x/user/month" or whatever.
HE in particular likes to set up incentives to draw more traffic through themselves. They do free peering to small networks at many IXPs (this doesn't give you full internet access like transit does) and tunnelbroker is also one of these things.