Just wondering. A few of my friends plan to go on Saturday, and I warned them about Saturday's line. So if possible, they want to get a Saturday badge on Friday. Is it possible? If not, I'll just tell them to go really early on Saturday. :)
My apologies if this has been asked recently. I'm somewhat in a hurry to find this out.
They can show up to the con on Friday and buy a weekend pass. I have known people to this before to avoid the Saturday lines.
Otherwise, you can't buy a Saturday pass on any other day than Saturday.