No, they are profiling for patterns that may indicate illegal activity. Carrying $9,950 through on one trip is perfectly legal. But, the person carrying $9,950 is more likely to be structuring transactions than the person carrying $300. Same with the person staying 86 days instead of 14 days. They get the scrutiny.
The whole "structuring" thing is exactly the kind of nonsense I am talking about. First they set a limit, then they come up with a new "crime" that involves observing that limit. I had a U.S. Treasury official admit to me in a meeting that they don't want to get rid of the FBAR requirement specifically because it creates an additional "crime" they can add to a rap sheet in order to maximise the leverage they have to get someone to plea out, or better yet, rat out. He explicitly referred approvingly to how spitting on the side walk laws are used for this purpose, and not actually to prevent people from spitting on the sidewalk.