That is a *horrible* compromise, because what will *cause* an outbreak is compromised herd immunity. And this compromise allows for compromise of herd immunity.
When the outbreak happens, cause by this excemption system, the damage is already done and children are probably already dying. And worse, this lets the disease get a foothold and provides it with a breeding ground to mutate from, which allows it to improve its ability to overcome vaccination.
There is NOTHING good about this "compromise". It's horrible. The only way to conclude it is anything but atrocious is to be completely clueless about how disease and vaccinations work.