Brought a friend that knew the basics of the game, but still needs to ask stuff like "Can I use this ability at any time?", or just needs to be reminded what menace does, stuff like that. Has a good concept of the basics though and wanted to come. I assumed they'd be fine, but they ended up playing against someone in game 1 that was completely wrong about card rules multiple times.
My friend played [[Drudge Sentinel]] and went to activate its effect after attacking, but the opponent said you couldn't tap an already tapped creature, which is false. My friend ended up thinking that Drudge Sentinels was way lworse, and that game came down to a few life points and could have realistically changed the outcome.
My friend also played [[Time of Ice]] and the same thing, selected one of their tapped creatures and opponent said they couldn't do that since it was already tapped. It's something I taught my friend but they didn't want to make a big deal at their first prerelease and call a judge.
Finally, they played [[Cloudreader Sphinx]] and they went to scry, but didn't know how to scry 2 (It's written in reminder text so this is partially on my friend), but the opponent insisted that they basically scry 1 two times. So my friend looks at the top, wants to keep, then looks at the top again and keeps it again.
It's almost to the point where I think my friend's opp might have been cheating, either that or they have an awful concept of game rules. They were in the bottom of the standings so it seems reasonable they're just not knowledgeable. I'm pretty pissed for my friend but they learned to call judges.