If a tomato has been growing in the sun the full time, IMO it is not likely to get sun scald. But if blight causes you to lose foilage before tomatoes have ripened under that foilage or if you prune limbs above unripe tomatoes, then the tender (not sun hardened) tomatoes can get sun scald. I have found that when a tomato gets a bit of a blush and fruit is picked at that not nearly red stage, it will still ripen in the house and have a flavor that is indistinguishable from one that ripens all the way on the vine. I generally leave the tomatoes on the vine until they are totally red, but sometimes when birds or pests are a problem, the fruits are picked at just a barely orange stage. IMO tomatoes are not like corn or butter beans which are best if eaten within an hour of being picked. A "ripe" green tomato will turn red and have excellent texture and flavor. The problem with commercial tomatoes is that they are picked before the ripe green stage and then are forced to turn red, but they never really ripen and don't have that ripe flavor or taste. Go ahead and pick that tomato. It will be delicious if growing conditions have been conducive to producing a top quality tomato. Enjoy!