Watercolor critique, please

[Patt Legg]

This is one of few watercolors that I have attempted in portraiture, actually character portraits. I find that I can stay more loose (maybe too much so) in watercolors as I tend to keep tighting up in oils. I have painted many years in oils and only a few in watercolors.
Mr. Spencer is a Blacksmith by trade, but I met him at a Flea Market as he caught me taking his picture. Upon being caught, I then approached him and he happily let me take others. I titled this "would ya take 5 bucks?" This has been shown many times and finally his wife bought it for him.

Question: I love being able to catch the "off guard" look in photos. If you approach them, they invariably will pose. Is this ok, to take pictures on the sly? I love doing figure paintings.

Patt