Use of own femtocel abroad?

[inquisitor]

I think operators will try to prevent subscribers to run their femto routers abroad, because that would cause legal implications due to the lack of license for the corresponding country and further that would mean losing roaming revenues.
At least Sprint's femto router has a GPS-receiver integrated, which is vital due to the synchronous timing necessary on CDMA-networks but according to some reports on the web GPS is not only used to get the exact GPS-based time on these routers, but it will also prevent use outside the US.
I don't know if UMTS-based femto routers do have a GPS-chip, but I think UMTS-operators will also try their best to prevent usage abroad. Alternatively to GPS this could be done by geolocating IP-addresses (this could be bypassed by VPN) and/or detecting if foreign 2G/3G networks are available.
Also check this article: Do you know where your femtocell is? - Femto Hub Blog - Femtohub.com | The Center For Femtocell News