Limiting card to a specific network

[SausageHack]

The situation is that I have a laptop that belongs to a younger member of the family, and it has internet access. The router we have has OpenDNS, which filters what she can access (i.e. she cannot access Facebook after 10PM, etc). The problem is that we have several unsecured networks in the area, and she can bypass all the filters by simply joining a different hotspot.

So is there any way to limit which networks can be joined? I have no problem paying for software, but I would prefer a simple registry tweak or something that a normal user wouldn't know how to circumvent. Thanks in advance!