Well, I had an EXTREMELY close-call IRL, where I almost got busted being logged into my E-mail account.

I was literally struggling to close the browser as my dad was trying to take Mom's phone from me, and I was just barely able to do so.

Dad was REALLY angry about the incident, and also rather suspicious of Mom (he still is, to a certain extent), but I tried to turn that metaphorical "lemon" into "lemonade".

I told Dad (without getting into specifics) the sorts of things that I would "hypothetically" be interested in doing online, and tried to reason with him.

Ultimately, he still was ticked at me, but I told him about my Pokémon Showdown account (a calculated risk), and told him that I was logged into it (rather than my E-mail), in an attempt to satisfy him.

I have NO intention of letting him know about my Paint account, my E-mail account, any of my friends here, or anything that might reveal any of those things, but I'm hoping that I can appeal to his (supposed) belief in "individual rights", and that he may allow me to leave home, and perhaps even help me to do so.

He's always said (whenever I asked about something he refused to allow me to do) that I can "do whatever you want when you're on your own", and that I can "leave whenever I want", and I intend on holding him to his word.

He agreed to talk with me (and Mom) at some unspecified time in the future (without my sister being present, as per my request), about these issues, and hopefully he'll be reasonable about things.
(And if not, I intend to do whatever is necessary to free myself, regardless.)