I hunt whitetails in WI and I love my FL gear. I wash as needed in scent killer soap and so far no problems. I dry everything outside on the line. My UA base layers will get pretty stinky when I walk way in on the public in the early archery hunts but my Llano does't seem to hold the smell, so to speak.
I hunt whitetails a lot, but not a lot from a treestand. I use First Lite merino frequently, can't say I have ever noticed a smell from washing. One of the things I like about the merino is the lack of odor when wearing.
I don't know if it's right or not, but I wash it once at the beginning of the season with scent killer and don't wah them again all year. Unless they get bloody. I do spray down at the start and end of the day and store all my clothes outside during the season. I had deer all around me from beginning to end of the season.