Give them a false one and see what happens .... unless you've already given them one as part of your "profile", in which case they will have to match.
Gmail occasionally lock me out, 'cos I use the incorrect password out of the million I have to try and remember ( or look up ! ) and they've asked me to lodge a cellphone number so that they can verify me. I've given them one from a pre-pay cellphone that isn't listed with anyone ( I think ! )