Rule of thumb is that when you have VPN fired up you don't never ever purchase anything from Steam Store. That is stuff that Valve actually cracks down on, hard. That said I have used VPN to unlock games early and still running my original accounts aka not once I have been temp nor perma banned for it.
Still you are going against TOS so you need to acknowledge risk that comes with using VPN to unlock early and accept that it's your personal risk to take, that on one is responsible if shit goes down.
New Zealand btw, 11 to 18 hours earlier access depending are you in EU or US.