Ah, I get it! You're pulling my leg!
Surely if such a thing had happened people would have discussed this instead of babbling about bland and safe! It would have been a big deal.
Or perhaps it was such a tiny part of the episode, tossed in in an attempt to be "edgey" it wasn't of much consequence. Perhaps it was a big deal for network, but in this era of cable it came off as more cute than anything.
It would've been a big deal, and more interesting if Watson walked in in the middle of it.