I'm not saying my own personal testing has proven anything to you. I'm asking you to prove it for yourself. Try it and see. But you already are, so...

Anyway if double-blind is what you need to be convinced, then by all means do the same test double-blind.[1] Shouldn't be terribly difficult to craft such a test for yourself.

[1] https://en.wikipedia.org/wiki/Blinded_experiment#Double-blin...