[mrtron]

It looks like the secret code was the test code, which accepts test cards:

4242424242424242 for Visa

And rejects test cards:

card_declined: Use this special card number - 4000000000000002.

[sah88]

You would think if you're using the live secret code server side it would reject charge tokens coming from the public test code.

edit: To be clear I haven't tested this and don't have time today with xmas and such.

[encoderer]

Like sah88 says, on the server when you connect to Stripe with your prod secret key, it will reject tokens made on your test key.