Re: What happens if...
"The is the Nine Seniles do not grasp there is a difference between unauthorized access and data theft and sharing Netflix passwords"
Actually, in this specific case of sharing passwords to services with friends and family I would argue that the "Nine Seniles" have in fact got the correct grasp - when a service such as Netflix puts in its T&Cs that you are not allowed to share your access with other people they, as owners of the service, are being pretty specific about the fact that you don't have any right or authority to delegate your access to anyone else - anyone who then uses your access password or codes is very definitely illegally accessing the system. I suspect Netflix (and similar services) will have a very definite opinion on whether or not sharing passwords is akin to data theft.
I haven't studied FB's T&Cs, but I wouldn't be surprised if they have a similar restriction, if nothing else to try and build their user numbers. As for a personal email account, well, people have ended up in the poo for just this before today - if the person who's account it is doesn't authorize you to access it then doing so is, at the very least, an indication that you're a bit of an arsehole and from there it's not too much further to being a stalker and/or divorced.
I just don't see what's complicated about this - either you have been granted legitimate access by a person with the authority to do so, or you haven't - one is legal, the other isn't. If the person giving you the access information is not authorized to delegate their access, then potentially you're both in trouble.