I'm guessing that Lauren only knows the 'official' stories-ones that would have gotten to the news media and/or the police. If she'd been actually prosecuted for kidnapping, that would be on the net. But most of what she did was with relatives and lovers, who, while not openly forgiving, might not want to seem vindictive, or look stupid themselves, for believing her. As for faking a terminal illness, doctors are limited in what they may share.
Most of what Summer did falls into the same category. Plus, saving Lola's life with the liver transplant may override the other things she's done, for now, at least.
So, what about the 'dark and stormy night? Is anyone as of yet not accounted for? Looks like Devon and Elena are together again, for a one night stand, at least!