What the recipient may say about the deed is not under the control of the doer. ;-)
But if the doer did the deed to the glory of GOD anticipating no personal thanks or even credit for the deed — that qualifies as a good deed done in secret. IMHO anyway.
I’m just goofing with you.
I’ve heard some people say that Jesus’s direction to give alms in secret means you can’t write a check to a charity, because then they know who it came from, and it’s not “secret.”