I'm just saying that she didn't notice, not necessarily that she would have particularly cared. Although she should, because even if it's a smaller TV (half of Millie's height, judging by the pictures), it would still be rather heavy-- too heavy for an eight-year-old girl to be able to move on her own, especially since the TV started out elevated on a stand of some sort, so it wouldn't just be a matter of pushing it somewhere.
Which is, I think, sufficient excuse to have Millie tested for super-strength.
Decades ago, there existed small portable televisions equipped with rechargeable batteries, and they were lightweight enough for a child to pick up and carry around. They had pretty small screens though.