Don't you think that is a little bit of an absurd comparison? I'm not saying all or even most women who cite rape in getting abortions are lying, I'm just saying it's likely that more than a few do.
As for the Holocaust thing, I'm pretty sure they have indeed caught people claiming to have been in the camps when they weren't, in order to claim property or money which they didn't deserve. I know after Hurricane Katrina a few years back, people went door to door for "donations" to the Red Cross, AKA their wallets. After 9/11, some people went door to door and asked via telephone for money to go to the relatives of those who died in the attack, and not all of them are legit. I think you're underestimating how scummy people can be when it is in their best interests to lie.