I don't really see why the Romans wouldn't have paid attention to Jesus. They were notorious at squashing any messianic uprisings.
This is not exactly true. It is true that the Romans killed messianic claimants. However, those that they did kill were generally revolutionaries. They romans were concerned with the
pax romana which included violently supressing any revolution, including would-be davidic/messianic claimants.
With Jesus, however, we have no indication that he went around publicly inciting romans or talking in revolutionary terms.
If the story of Jesus entering to Jerusalem on a donkey is true and the throwing down of people's garments actually happened, the Romans would have been quite upset with this. This was a known way of the people acclaiming a king.
If the incident actually happened, it would only have meant something to Jews. The passage of the ride into jerusalem is explicitly connected to jewish prophecy:
τουτο δε ὅλον γέγονεν ἵνα πληρωθη το ρηθεν δια του προφήτου λέγοντος/touto de olon gegonen hina plerothe to rethen dia tou prophetou legontos/ and all this was brought to pass in order that that which was spoken through the prophet saying...
Basically, to assert that this incident would have any significance to a roman is more than a bit of a stretch.
Word would have got to the Romans
Through jews, yes.
After all, if the Romans could behead Theudas and scatter his followerer just for gathering at the River Jordon while they waited for Theudas to part the waters, how much more possible is it that they would get rid of a leader of a messianic uprising?
1) You have to explain how they would know. Jesus' actions on the donkey, if they happened, would mean nothing.
2) You aren't describing what Theudus did altogether accurately: From Josephus Anti. 20.97-
pethei ton pleiston ochlon analabonta tas ktesies hepesthai pros ton Iordanen potamon auto/ he persuaded most of the crowd/people to follow him,
having taken up their possessions, to the jordan river.
Important to note is a) the gathering of a large number of people and b) they aren't simply "waiting around for Theudas to part the waters" but rather
analabonta tas ktesies.
3) We have very little information about what Theudus did and how the romans may have been alerted. By contrast, we have four fairly complete and detailed (and by ancient standards historical) accounts of Jesus' mission. Even if we discount the statements concerning Jesus'
ad hoc trial in front of Caiaphas, we are still left with the fact that we have no clues as to how the romans would have been so concerned with him without Jewish cooperation.
They certainly weren't known for their benevolence nor did they ever respect the sensibilities of the Jews so that makes me suspicious that they would "bow down" to any requests that they did not feel like doing. Saying Pilate had "no choice" is ridiculous. He had the power to do what he wanted and he usually did.
True enough. However, if we are to believe sources like Philo, Pilate would not have wanted to do anything to please the Jewish populous. If there is any truth to the story that he did not want to execute Jesus, it could be as simple as not finding enough reason to care about Jesus and not wanting to be told what to do and who to execute by the jewish elites.
It is said that the Sadducees were pro Roman and against Messianic uprisings. Maybe they would know the significance of the donkey and garments laid in Jesus path and enlightened the Romans??
Very plausible. However, it is no less plausible to think that Jesus was brought before Caiaphas.