That’s what I do. There’s been plenty of times where the conversation never actually begins
A more mature way would be for "first offenders" to politely reply hi and help them with whatever they need and then when everything is done politely point out that asking directly would be better next time, perhaps with a link to some version of nohello.net. With "repeat offenders" sure, go ahead with what you are doing.
In my experience, even the comically over the top people-persons will be curt to chatty people if they're swamped with a task that doesn't revolve around verbal ability.
They'll also bounce back to "they won't put down <tool> and talk to me" gossip about the nerds once their deadline pressure is released. But whateves, that's life.
Intentionally ignoring people or otherwise being difficult out of spite is immature and disrespectful. That said, I see no reason to sit and wait for a response. Wait until I'm free (if it was urgent he should have specified that), reply "hi", tab out, and the thread goes back on the stack with all the others. No special treatment one way or the other.
Is tab-h-i-CR-tab really so onerous? Personally it doesn't even interrupt my line of thought.