Texas border town airport immigration reviews are far more intrusive than anyone will ever generally see in PR. Along the TX border they are checking for suspicious border crossing activity and Mexicans who have entered the US border zone but have not completed the entry formalities to go beyond the border zone (as any domestic flight would take you). At MFE for example, pretty much everyone departing has to see an immigration agent up close as you hand your docs to the TSA agent. Same checks are on highways, and it’s been that way for many, many years; it’s not a recent development. None of that is of much concern in PR.

I cannot imagine taking my passport to go to PR or Alaska. When you’re talking about 1 in a million events, I could also just as likely lose or damage my passport somehow on the trip. Were I not a US citizen I would do so, since as mentioned, that is required and prudent anyway.