I highly doubt any airline staff are on your flight (or even remotely) counter-hacking one in a billion passengers messing around with the in-flight WiFi. That $30.75 they're not getting doesn't justify anyone looking into it.
Plus, the free tier is usually set to a very low QoS such that chat is pretty much the only thing you'd bother doing. Short videos will download in a reasonable amount of time but on average, the actual data rate is small. There's only so much bandwidth available and they want to make the $30 somewhat of a value for those needing full Internet access. One person absolutely saturating the limited bandwidth allowed for the free tier is not going to make much of a difference for everyone else but it could be an issue if everyone was doing it (like if a VPN was all that was required to bypass the restrictions).
