Want to discuss the chain of events and potential outcomes regarding the note left behind by the heavily fortified zombie lake guy. "Congratulations on winning but you still lose" and the middle-finger drawn for emphasis (or words to that effect).
(Note also that we assume up until a bit later that said zombie lake guy had already met his demise as Rick and Aaron got this far unchallenged.)
So, obvious "Chekhov's Gun" event, right? And the assumed and obvious payoff was when Rick and Aaron have arrived back at Alexandria to discover Negan has made a surprise appearance but the guys at the gate are going to offload the goods from their truck first (and buy Negan a little more time to dance with Spencer before gutting him like a fish). They see the note, they make it out like it is an insult meant for them, they beat on Aaron for a while. End of.
But I got to thinking. It stands to reason that well armed and fortified survivors would take extra care to guard their "stuff". Have we had any previous incidents where something that the survivors found or came across which appeared to be abandoned by previous post-apocalypse survivalists was 'booby trapped'? Should we not read any more into the note or could there be further surprises in store for whomever delves more deeply into the contents. Rick and Aaron just laugh it off and maybe don't look to carefully because they know they'll only be giving it to The Saviors. And the Saviors haven't done anything more than a cursory examination and then load it up in their own trucks.
Then of course we see the boots of someone at zombie lake observing Rick and Aaron as they take their leave. And at the very end we see boots again of someone observing Alexandria under cloak of darkness and then, I think, dropping inside. I may be reading too much into it but that 'Bootsy' first showed up at the lake I'm thinking it was the original occupant of the zombie lake barge taking to watching to see who comes and where they go. Maybe it is a tracking device of some kind in the "win/lose" box.