There were other USAF personnel who were support and technical that did go "over the river" to places we called Lima Sites. Look up Lima Site 85 and see if anyone really believes in the concept of a Non-Combatant in the military. Oh, and as for being stationed stateside when the NVA moved south in April of 1972 there were quite a few GI's who thought they would be in the states for their full tour of duty that suddenly found themselves in our tropical paradise within just a couple of days.
You can passively block it, yes. There's nothing preventing you from building a Faraday cage around your home. You cannot ACTIVELY block it though (i.e. broadcast signals to intentionally interfere with it).
Get aluminum siding on your house and you WILL be in a Faraday cage! The voice of experience says so.
However, I know that in my case sunlight in my bedroom window makes me wake up more easily and feel more refreshed than being awakened in darkness. This seems to be at least somewhat invariant as to the actual number of hours of sleep I got within limits. Since I inhabit the temperate zone in the Northern hemisphere I would much prefer to just hibernate through the 3 to 6 months of winter (depending on latitude) we have here and not worry about changing from DST and back.
Yes, I know that everything has changed in 40+ years. I was there in 1971 and 1972 and it was a different world and a different place then. Also I was aware even then that the foods used and preparation varied widely around the country. Where I was was right on the border with Laos and there was much overlap between the Thai and Laotian foods. Even the ubiquitous Khao Phat fried rice varies widely around the country.
I did eat as much of the local food where I was as my taste buds, and system could handle and only got amoebic dysentery once, and that was from some ice in a drink I think. By the way, eating the local food was one of the LEAST risky things I was involved in while I was there.
I saw a giant Mekong catfish lay on the side of the road for at least three or four days before it was considered "ripe" enough to use in food. When I was there refrigeration was rare and most food sat out in heat and humidity for extended periods. The climate was even a bit more that I was used to -- and I was born and raised in the deep south before air conditioning was common. The aroma of a Thai open air market is to say the least unique. Thailand is one of the most beautiful places I have ever seen, and the people are the friendliest and most open anywhere, but eating "real" Thai food is something I was never able to really appreciate.
There are places I have eaten in the US that have excellent Thai food, but it is not what you find the Thai's eating in Thailand. Maybe Anthony Bourdain can eat real Thai food, but on a recent episode of his show it appeared that even he was having a bit of trouble with some of it.