It is interesting that Paul and Silias appear to have caused greater fear among the Phillipian leaders from being known as Roman’s than from being known as Christians.
Act 16:20 And brought them to the magistrates, saying, These men, being Jews, do exceedingly trouble our city,
Act 16:21 And teach customs, which are not lawful for us to receive, neither to observe, being Romans.
So we have..
Act 16:38 And the serjeants told these words unto the magistrates: and they feared, when they heard that they were Romans.
Acts 16:38 Gill
And the sergeants told these words unto the magistrates,…. They returned to them, and acquainted them with what the prisoners said:
and they feared when they heard that they were Romans; they were not concerned for the injury they had done them; nor for the injustice and cruelty they had been guilty of; nor did they fear the wrath of God, and a future judgment; but they were put into a panic, when they found the men they had so ill used were Romans; lest they should be called to an account by the Roman senate, and be found guilty, and have their places taken away from them, and their persons punished.
Rainbow Trout 