1 Kings 2:39 (ESV)

39 But it happened at the end of three years that two of Shimei’s servants ran away to Achish, son of Maacah, king of Gath. And when it was told Shimei, “Behold, your servants are in Gath,”

It appears that Shimei did obey the restriction that Solomon put upon him for a period of three years. It may be that nothing happened during that time that tempted him to violate those restrictions. We do not know, but at the end of those three years a circumstance arose that led him to violate the king’s command. Two of his servants ran away from him. Interestingly, the writer tells us that they went to Achish the king of Gath. Is this a way of saying that they fled to that king’s jurisdiction, or are we being told that they sought refuge from any search that might be made for them? If the latter is the case, Achish’s protection did not succeed in keeping them from being found.

Was this the same Achish that had given aid to David (1 Samuel 21:10–15, 1 Samuel 27:2–12)? The probabilities are not high when we consider the number of years separating the events. The question is one of curiosity, and it invites speculation that would take us from the main point of the narrative.

The news of the location of their flight came to Shimei. Given the means of travel in the tenth century BC, Gath was not a near neighbour to Jerusalem. That means that if Shimei were to follow them there, he could not argue that he did not go out of the neighborhood of Jerusalem, nor could he argue that he had been gone for only a short period of time.

Therefore, if you ask the question, What did Shimei do? you are asking whether his obedience to Solomon held firm.