I read it originally from a poster on a privacy/security reddit who was reporting their personal experiences. It isn’t the most reliable source but in this context I consider it worth accounting for anyway, as what the person described experiencing is both possible and plausible. For anyone who is serious about preventing these sort of privacy breaches, the open wifi vector should absolutely be considered and guarded against if possible (easy but less comprehensive approach would be to see if there is an airplane mode on TV, harder but more reliable is to physically disable or shield the wifi module on the TV itself).

Some TVs have been found to continually scan for open wifi networks to connect to in order to ship back the telemetry they gather.