No, I meant that's the average speed I get (so if we were splitting it I assume our speeds would each be half that when downloading / streaming simultaneously).
In the worst case, because of buffering, your Netflix video might take an extra 10 seconds to start and then you'd notice no interruptions (unless you're skipping back and forth). But even that worst case would be unlikely to really be an issue.
For example, are you ever interrupted by someone else in your household turning on another TV? It would be similar.
You wouldn't want to share with your neighbor if they are actively abusing this with torrents or some other constant high bandwidth activity, but ideally you'd pick a neighbor you already know well and can trust.
You're probably right though.