I will not say that it don't happen that Muslims become Christian but I do know you can go on youtube and see hundreds of fake Muslim converts to Christian. There are things in Islam that just are not known to the public. You could read the Quran 100 times and never know such things. That's how Muslims know their fake.
and we are going to take a Jewish voice on that?
Any examples you can offer of "fake" Muslim converts to Christianity? Because finding exposed fake Christian conversions to Islam is quite easy, e.g.:http://www.answering-islam.org/Hoaxes/abuishaq.html
The knowledge of Muslims of Islam in general isn't so high, so even those born in Muslim families in Muslim countries wouldn't know the things you are alluding to, let alone be able to spot.
Btw, Jinnah, the founder of Pakistan, all his descendants are/were Christian (I understand that one has apostacized and become Parsi, his father's original religion).
Interesting; where did you get the information that Jinnah was of Christian background?