Laptops, at least in the US, are not banned in checked luggage[1]. The airlines may have different rules, but generally the airline is not the one inspecting your bag, TSA is.
And that itself is a recent policy change from just in the last two months; as of January United's official policy [1] matched the FAA's in only requiring checked devices to be powered down
Ah, good. We're currently reliant on unpaid, probably-not-too-happy workers for fire safety. Sounds like a great time to stay off an airplane in the USA.
It's a bit of a grey area on jurisdiction because FAA cares about flight safety (fires) whilst TSA is primarily looking for terrorists.
United Airlines, however, prohibits laptops and tablets:
* Remove any lithium batteries from electronic devices stored in checked bags.
* If batteries cannot be removed, these devices must be stowed in cabin bags only.
* Store any spare batteries in cabin bags.