There are so many unnecessary “clues” pointing the other way, though. Like why bother with the otherwise pointless digression of taking time to establish that John and Mary didn’t arrive at the aquarium together? Under the silly and over the top theory, Mary was getting kitted out with a bulletproof vest and a blood pack.
But we can have our cake and eat it too. Given that Sherlock-shaming is such a major theme of the show, we say that Sherlock investigates, comes to believe the silly and over the top theory, and rushes over to John’s place to explain. At the end of his explanation, he tries to rip the wig off of bus lady’s head, only to find out it’s very real hair (for bonus points, the very real hair of Mary’s long-lost identical twin.) Sherlock was wrong! John then gets to go off on another tirade about what a terrible, awful, deluded person Sherlock is for disturbing him when he was just finding peace, and the writers get to continue to act like they’ve slipped some Serious Drama into the diet of nonstop blarney.