No, they are in series, which, as you rightly point out, is a bit more risky than parallel because if the connecting wires break, that is it. The drain on the batteries will be equal though so you need to ensure that both batteries are fully charged as well otherwise you end up with one battery dying first, taking the other with it.

I use 2x 2S 2100mAh 2S1P LiFePO4 batteries in The Honey Badger 3.0, making it 4S1P but can go to 6S quite safely. The upshot of a series connection is more voltage so it is a easy way to get to 6S without needing a fairly weighty battery but the capacity remains 2100mAh so they do need charging after one or two fights. I keep a spare matching set around so I can simply swap out for the other set and charge the first set in the meantime.