Hypocrisy: Where's The Line?

One friend made me think of this topic when we were talking about a scenario. In this scenario, the mother-in-law is criticising a woman 'coz she's chosen a good private school for her child (which proves to be rather expensive). The mother-in-law wants her to send the child to a much cheaper school, but the woman is determined to give the child the best education she can give him, even though it means she has to take out her own savings to do so.

So, when the mother-in-laws keeps on giving suggestions, the woman just nods and says "yes, yes, yes, that sounds good indeed", but behind her, she just does whatever she wants for the sake of her child.

One friend said that she can't do what this woman does, 'coz she feels that it means she's being a hypocrite. I guess if she were in this woman's position, she'd fight with all her might to explain it to the MIL even though it means there might be a verbal fight between them.

What do you think of this scenario? What's your POV? Where's the line between being a hypocrite and being "a peacemaker" (at least in this scenario the woman can be called that, I suppose)?

IMO, I think the woman is clever enough to balance things out. She respects the MIL's suggestions and accepts her criticisms, but she still does what she believes to be the best for the sake of her own child. After all, it's HER money and HER child, not the MIL's money and child.

I believe in honesty, but I don't believe that brutal honesty helps out in many scenarios (even though some people may think it's a kind of hypocrite act).