Suppose a non-observant parent gives a (monetary) gift to his/her adult child, but asks that the child not remove 10% to give for tzedaka ("Your mother and I saved this money for you, not for other people.")? What would be the correct halachic response of the child, taking into account the halacha of kibbud av v'eim as well as the halacha of tzedaka?
Agree to the parents' request and don't give ma'aser.
Agree to the request, but give ma'aser anyway (i.e. lie).
Refuse to agree to the request, and give ma'aser against the parents' wishes.
Do not accept the gift.