It was drama when Eflin did it too, and he was a pitcher who wasn't even going to be used in a game. You'd have to tell me who else has been sent down in such a way in the past, I can't say whether or not I remember if Dom Brown or Cody Asche did that. Not even sure Pivetta did, but again, pitcher.
I think all of the flare-ups with Williams were overblown and this doesn't appear to be flare-up either, most likely because Klentak and Kapler are not like the guys who were running things back then; when I say it's drama I am not being critical of Williams, merely speculating that it speaks to his understandable unhappiness with the situation, about which he's certainly been a good soldier. This is his job and he's entitled to whatever perks/days off the CBA allows but in this case I think there is something to be said for sending a message - to other teams as well - that he's bummed but eager to get down there and get his ABs.
Probably his agent won't make a fuss or demand a trade since he's still busy figuring out what to do with the money he made off costing Williams his job! 
Plus he knows the trade is coming regardless.
