I very much agree that LS's friends, acquaintances and anyone else she may have come across the night of her disappearance should not be needlessly pummeled by the media or the public, should not be called out and harrassed and slandered on the internet. However, I think there is an admirable way to handle the situation, as a friend or as a POI that I think a lot of people in this case have not seemed to have done, which has resulted in them being harassed, etc. As a POI, essentially I would do what CR/MB seem to have done: get a lawyer, cooperate fully by making full statements to LE with the protection of your lawyer so that LE doesn't potentially twist your words, take an LE administered LD test, readily submit to DNA tests and searches of your apt./car, etc. ETA: Oh and also, stay in the area for at least a couple of days to make myself available.
In addition to this, I would add reach out to LS's family and tell them you are very sorry they are in this situation and that you hope she is found and will do everything you can to provide necessary information to help find her. I would also add don't tell the media they are 'ruining your life.' Just stay out of the media as much as possible and if you must speak to them just say 'I hope she is found soon,' 'I have said everything that I know' or something along those lines.
As a friend, follow basically the same guidelines in reaching out to the family to express how sorry you are and let them know you will provide any information that could be helpful but that at the same time (if true) stress that since you were not with her, you do not know very much. Also let LE know that you will be happy to provide them with any information that may be helpful. Again, stay out of the media. If you make reports in the media simply say I'm very sad my friend is missing and want to find her very much. She is a great person, I wish I knew what happened, etc. However, I think her friends have made mistakes in that they have alternately been too forthcoming with the media or else they have come off as rude. All that her friends had to say when approached by TG was 'I'm sorry, I don't have any information I can give you.' Not 'leave us out of this.' And certainly not having anyone at your house driving a car toward reporters either. That just makes them look immature and leads people to make negative assumptions about their character or their friendship with LS. Whether they are guilty or not, they just haven't made the best choices in helping to determine how they are portrayed.
Finally, I think these friends and POIs should have been made aware how important it is to show themselves in a better light from the beginning. Someone should have made sure they knew that however small their connection to LS's disappearance might be, they should prepare for an onslaught of media/public attention would be on them and should probably respond accordingly by making their facebook, twitter, etc. private or else prepare for people to invade it, repeat it and talk about them. Anything publicly available on the internet (in addition to social media, also blogs, statements to the press, message boards, etc.) can easily be taken as fuel to the fire by any stranger with any kind of intentions (good or bad) who has internet access and an interest in the case (A LOT of people).
I don't blame these POIs and friends for being taken aback by how much negative attention they've gotten, maybe this is all easy for me to say as I am removed from the situation and a little bit older/more mature but they could have avoided a lot of the suspicion focused on them if they acted as above^^^