Just subscribed (Freemium) to using your CORS Proxy. It works perfectly.
It will be used in a mapping system in which users subscribe by making a donation to charity i.e. there is no commercial gain for me as hoster.
Yours terms say:
What if I exceed my plan limits?
Depending on your plan’s specification, you will either incur overage charges or be suspended.
The 100 call limit per day (at the moment) should be ample for users using the feature that requires CORS. The suspended worries me. Is that suspension just for the rest of the day or permanent. Hopefully the former. Is there a way I can detect the daily limit has been reached so that I can pop-up a message to the user.

Thanks

Ray Crowther