FFF .... Cabair flying schools operate a similar scheme. Hirers can only go to unlicensed fields with the CFI's permission, & after he has seen details of the field, weight+balance, a/c performance, AND the hirer's flying experience.
This does prevent inexperienced hirers taking an aircraft at MAW, into a muddy 400m farmer's strip
There is no problem going into the well known unlicensed fields, such as North Wield.
One point about going into licensed fields outside opening hours. It is wisest to ask permission first.
I understood that most such airfield operators, only allow the home-based aircraft to land when the field is closed. Any other aircraft has to get prior permission, by phone. Some fields have planning restrictions on flights, after a certain time in the evening or at weekends, so have a complete ban on movements outside the usual opening hours.