Vodafone Bill Pay Upgrade Question

[AbbeySider]

I am a vodafone billpay customer and I am wondering if I upgrade my phone, is there anything stopping me from giving my upgraded phone to someone else?

I currently have a HTC Desire which came unlocked/sim free.

I am thinking up "upgrading" to a HTC Desire S for €110 and just giving that phone to someone that needs one rather than them paying €400+ for it.

Is there anything stopping me or any catch?

[Candyman]

In short... NO!! :-D