While it's not a requirement, I would highly recommend it. Even in flight, the drone's built in access point continues to allow new connections. I have connected as many as 4 devices at once, 3 running the Tello app but only one receiving video. I was not able to take control from the app that had control first, but I only tried this once. The good thing is, unlike some other smart drones, this one appears to be locked down to some degree, and doesn't allow simple connections like telnet, as an Nmap scan only revealed one open port, 9999, and I could not get a response from whatever process was listening on that port, most likely because it requires some sort of security. That means one can't easily gain access to the onboard OS (probably BusyBox), so they have taken some effort to secure this it seems. I really haven't tried any more advanced techniques to gain elevated access, but being able to connect more than one device at once presents enough of a security risk to me, but then combine that with the fact that if you leave it powered on while charging, you've just given anyone with an Android or iOS device a free peek into your home, that is enough to compel me to password protect the access point.
