Why would I do that? There's nothing happening that needs initiative to resolve.
Maybe in your game. Not in mine, and not in Jeremy Crawford's:
https://twitter.com/JeremyECrawford...tp://www.sageadvice.eu/2015/01/14/hex-effect/
You just hexed the Kings intelligence. Is he not
thinking?
And I don't know about your game, but in my game laying a hex on someone is obvious. You are magically cursing them. Channelling the foul powers of your dark patron into them. Your eyes turn a funny colour or you hurl stream of insults at them. Whatever.
Just because an ability lacks any fluff text as what it looks like doesn't mean it doesn't look like anything. Youre free to rule in the absence of any text that says it looks like something specific that it doesn't look like anything at all, but that's up to you.
If a player in my game said he was going to lay a hex on the King, then that is an offensive action that the king gets to respond to and initiative is declared.
I'm not saying you have to run it that way. Go nuts with whatever feels right to you.
If you read what I wrote, you'll know I share this opinion--it would be better from a roleplaying perspective for Hex to nail this down one way or the other by specifying HOW you transfer the Hex, instead of just handwaving it as something you do with "a bonus action." After all, if you leave everything undefined except in terms of combat jargon ("bonus action"), you (the game designer) are just asking for DMs to interpret everything through the lens of combat, whether that is intended or not.
To be honest you're the one who is inferring that by not including any fluff text description of what laying a hex on to someone looks like that it doesn't look like anything at all.
It might be possible to conceal the fact that you're hexing someone. But I can assure you in my game if your warlock tryed to hex someone while they were looking right at them then it would be initiative time.
And also the game is kinda described through the Paradigm of combat actions within combat encounters. Zooming out a step it is next described in the framework of the adventuring day.
I'm not saying that you have to run your game in such a way with series of discrete encounters over the course of a day and all abilities described in the context of those encounters. I'm just saying that it's pretty clear that that is the inferred framework of fifth edition D&D.
You can repudiate that and allows shenanigans like bag of rats and 20 short rests in a 20 hour period if you really want to. I'm just saying I don't think that's what the designers intended the game to be.