Say good bye to your moms credit lol. I don't know if jail time would be a consequence but the outstanding balance will most likely be referred to a collections agency that will bug the crap out of her to pay. She can ignore it if she wants but she will find difficulties apply for things that are credit based in the future like financing cars, renting apartments, even opening post paid cellphone accounts like the one she just opened to get that iPhone. Foolish thing to do but it's her choice.
I once knew a guy who would open phone accounts to get smartphones for 200 or so dollars and sell them to make a profit and just not pay the service provider after that. Now he can't even open an account with any of the major carriers, or he could but not without paying some insane security deposit lol. Meanwhile all the outstanding bills that he haven't paid are killing his credit by the minute I wouldn't be surprised if blockbuster refused to let him start a membership with them lmao.