Hey there, although I don't live in Chaing Mai, I am located in Bangkok. Generally, from what I've heard carrying knives is a no no. At least in Bangkok. Laws in Thailand are difficult, confusing, and sometimes just stupid. I do carry my Leatherman 99.9% of the time and haven't ran into any trouble yet. I think multi-tools are more accepted. I've whipped out knives to cut straws or open stuff in public before, and again, haven't gotten into trouble yet. You may not be as lucky though.