It depends on friends. Moreover, our thoughts can change with time. When it comes to meeting with family, our parents have good power to convince us and in case of your friend same thing happened and I won't blame them for it. But I must blame them because they didn't inform you earlier.
Yeah you might be right about it not being totally their fault but seeing how they're not totally in control of their movements, how about they stop being so certain when answering questions about the said movement.