LG smart TVs caught logging audio with screen off and snooping on local devices
(www.notebookcheck.net)
Or... If your neighbor has an open network... Or the TV has a secret networking protocol that allows it to talk to other LG smart devices that are on a network. Or it looks for phones that have the LG app installed.. You get the idea. Once you put wireless capabilities in it, there is any number of ways it can leak your data out.