As with any modification to your car such as a tow bar, stickers (yes, really) or a performance air filter, you are obliged to inform your insurance company and this responsibility lies with you. However, it should not be assumed your premium will increase as a result of fitting an ezero product. As yet, we have yet to hear from anyone that has had their premium increased, and usually the insurance company just thanks them for letting them know.
At the end of the day, the obligation is yours. If you choose to inform your insurance company, the ezero should be described as a fuel additive for emission reduction or an emission reduction unit. Please note, the ezero does not affect your speed or your safety and isn’t visually desirable (i.e. appealing to thieves).