I do it in hopes that it works. Don't know of any research on the subject.

Unless you're interested in immature tomatoes (like fried green tomatoes...pretty good really), it seems there should be some basis for thinning the oncoming crop to put more sugars toward growing/ripening older fruit.

I also wonder whether the tomato itself will simply stop the new growth all on its own due to the cold weather. Picking off each flower is time consuming.

Depends upon how many plants you have. I typically grow just 3.