Tonyblack wrote:We don't know if he was actually wearing the lilac in the original timeline.
Uh-uh. The following conversation happened in the original timeline, just after Vimes arrested Carcer:
Night Watch wrote: Vimes stopped at the entrance gates. Overhead, another lamp flickered. He dropped Carcer to the ground.
“You knew? You bloody well knew, didn't you?”
“Not until, oh, one second ago,” said Vetinari. “As one man to another, commander, I must ask you: did you ever wonder why I wore the lilac?”
“Yeah. I wondered,” said Vimes.
“But you never asked.”
“No. I never asked,” said Vimes shortly. “It's a flower. Anyone can wear a flower.”
“At this time? In this place?”
“Tell me, then.”
“Then I'll recall the day I was sent on an urgent errand,” said Vetinari. “I had to save the life of a man. Not a usual errand for an Assassin although, in fact, I had already saved it once before.” He gave Vimes a quizzical look.
“You'd shot a man who was aiming a crossbow?” said Vimes.
“An inspired guess, commander! Yes. I have an eye for the…unique. But now I was fighting time. The streets were blocked. Chaos and confusion were everywhere, and it wasn't as if I even knew where he could be found. In the end, I took to the rooftops. And thus I came at last to Cable Street, where there was a different sort of confusion.”
“Tell me what you saw,” said Vimes.
“I saw a man called Carcer…vanish. And I saw a man called John Keel die. At least, I saw him dead.”
“Really,” said Vimes.
“I joined the fight. I snatched up a lilac bloom from a fallen man and, I have to say, held it in my mouth. I'd like to think I made some difference; I certainly killed four men, although I take no particular pride in that. They were thugs, bullies. No real skill. Besides, their leader had apparently fled, and what morale they had had gone with him. The men with the lilac, I have to say, fought like tigers. Not skilfully, I'll admit, but when they saw that their leader was down they took the other side to pieces. Astonishing.
As you can see, Vimes had previously "wondered" about Vetinari's habit of wearing the lilac on that day.
About the cigar butt and beer bottle, I think they don't matter. I think Lu Tze just acted annoyed so Vimes would stop persueing a pointless digression to their conversation.
So why didn't Lu Tzu just tell younger Vimes about Carcer and where to find him easily in the future, and avoid having older Vimes & Carcer being sent back in time and getting Keel killed ahead of schedule?