https://www.reddit.com/r/magicTCG/comments/e3owi7/update_arabian_nights_mountains_swapped_for/So story time: Girlfriend of OP goes to LGS, get "prey'd upon" by trading cards (which aren't hers, for the record) of OP for "newer prettier art!" to put in OP's modern deck. She gave away $1,000 and he doesn't "have the heart to tell her because if I do she'll quit Magic and I don't want that!"
Bunch of white-knights come in and say "Oh, I totally understand OP!" (Which sounds heartless when It put it like that) and other more reasonable folks are like "well, she screwed up and you should tell her gently that she did and next-time she'll know better." Generally the thread is a whole bunch of

while folks are "delete the reddit, Lawyer up, hit the FLGS owner."
So now the link: OP tells her, she wants to quit Magic over it (OH NO!!!) while the FLGS owner is like "tough-break, dude. She willingly traded them, it wasn't theft." (Which is the logical answer for this) and OP still wants to pursue legal action to get the 4 of the 6 he didn't get back... back.
Like, I feel for him but: Why is he letting her play his Modern decks unassisted/unseen at the FLGS and why is she trading cards without his permission (which IIRC in the older OP he
stated such a thing of not doing)?
I think the biggest take-away here is that newer players need to be told "these cards have value, all. of. them! Even basic lands have value because of their art! You should check for the value before entering into any trades!" and this would've solve the issue (hopefully) of said Girlfriend trading things (that aren't hers) for cheaper cards without knowing that she's giving away more expensive cards over the art. The sooner you do it, the better so they understand that a trading card game like Magic has a secondary/value market.
And while I feel bad about the girlfriend no longer wanting to play Magic: She screwed up, the trade [as scummy as the dude was about it] was legal: She agreed to it, she wasn't coerced (based on OP's writing)//twisted into giving them away unwillingly and she did it under her own volition
without knowing the value of the cards so it isn't "theft" so the cops and FLGS can't do shit about it. And taking the dude to court isn't really going to get his cards back per-se if the dude
really did sell them (possibly by eBay or something to get them gone fast) unless there's a legal paper trail and even then see: Girlfriend willingly traded them away and it was a legal trade. Similar to how some folks in video (and non-video) games give away older items to newer players. Just in this case it's like the reverse and had more value.
https://www.reddit.com/r/magicTCG/comments/e3owi7/update_arabian_nights_mountains_swapped_for/f94nd7j/
She willingly traded it under her own volition, dude. Not the store (or other dude, but kinda is the other dudes) fault she traded unknowingly of the value.
https://www.reddit.com/r/magicTCG/comments/e3owi7/update_arabian_nights_mountains_swapped_for/f94no2a/BASED as the kids would say.