My understanding of your arrangement -
When Netflix sends you an email asking you to approve your "household", it essentially means that you have now changed location and hence you want to have a new IP be able to access Netflix on the TV.
Each member is able to approve the E-mail by themselves instead of depending on the administrator due to the E-mail shared between the group.
By each member doing this several times a month, the Netflix "Household" is shifted from one IP to another frequently.
In an average real life scenario, you might shift houses once every year or once every 6 months.
So when the Netflix "Household" keeps changing between the same set of IPs/IP ranges 3-4 times within a month and this keeps happening every month, wouldn't Netflix easily be able to filter out such accounts?
Happy to know that it works though. Anything to bleed these corporations dry.