this is certainly my experience. long long ago (mid-80s) as a teenager traveling solo (15+, able to fly alone) coming back from cent. america into IAH, I remember an airline person, while in the customs line, but before customs exit, came up to me and told me after customs to go to the gate. I was young enough to not process just how unusual that was, in and of itself.

I then got what is still the most thorough, exhaustive examination/inspection I ever had. I think the agent doing the inspection was genuinely surprised at the end, I must have closely fit a profile they had had good results using in the past. To the great credit of customs, the entire event was very professional.