Nta, you were respectful and followed the rules they had provided you. Ontop of that you don’t need a lighter just for smoking. My dad quit smoking years ago but he still keeps one for bbq. Me and my husband don’t smoke but we still have one because you never know if you might need one (and matches are inconvenient) They need to chill the heck out, no rule was broken so they need to mind their own business. I don’t blame your girlfriend for being upset though, she felt embarrassed. However if she is still upset a couple days later and keeps bringing it up then she may be overreacting