can you draw lines on shabbat?

What did Yaakov Avinu learn in Yeshivas Shem V'ever? He spent 22 years learning in yeshiva long before klal yisrael received the torah?!

am i allowed to sit in a non-kosher restaurant with a Kipppah? Can i eat a double-wrapped kosher meal? What if the meal has no kosher symbol on it, but I reserved Kosher and the waiters say they got it delivered as special kosher, and everyone else is being served on normal plates etc. while i get a tin with a plastic cover? (this happened last night at a dinner). can i assume its kosher?

I need informationb on halacha and birth control. thank you

I'm directing this question to Rabbi Becher, because I've had good luck getting completely intellectually satisfying answers from him in the past on closely related questions--but I'm open to anyone who feels they can hit a home run on this one: I am one of those people who have turned to religion in some measure at least because Rabbi Kelemen's incunabular argument from his "Permission to Receive" made it intellectually difficult, to say the least, not to believe that the Jews had a revelation from G-d at Sinai. However, from time to time I encounter or think of counterarguments. When I do, I like to address them with a rabbi. In this case, someone challenged the logic that all Jews must be descended from the group who witnessed G-d's presence in Sinai with this story, which seemed plausible to me: "How do you know you're really descended from such a group? How do you know your ancestor wasn't some devious Russian who observed 'Those Jews seem to be successful. I'll move to another town and tell everyone there I'm Jewish, and like that I and my progeny forever will become a part of this successful people.'?" For argument's sake, let's say the devious Russian was a woman. If such an event transpired in Russia or anywhere else, perhaps even more than once in human history, then doesn't it cast doubt on [A] the veracity of any individuals claim today to be Jewish and [B] the claim that anyone is descended from a group of people who experienced collective prophesy that day at Sinai (that is, couldn't everyone who claims to be a Jew today actually be descended from one of these devious gentiles)? The only problem I can find with the latter question is that there must have been at least some group publicly identified as Jews that the supposed copycats were interested in joining, but even that problem doesn't prove any one of us is actually descended from an authentic Jew. Thanks in advance for your help in fully trouncing these counter arguments. Good Shabbos.