Am I in the wrong?

So my 4 yr old sees her biological dad once a month for about 4 hours (his choice, he's supposed to have her one full day a week). She often cries when she's there and he rings me to come get her early. His family live about 3 hours away and have never travelled to meet her but have suddenly asked him to bring her to them (there's a family wedding coming up and they want a cute flower girl). He is now expecting me to let her go away with him to this unknown family for a few days and thinks I'm being unreasonable because I've said no. I think they should travel to meet her and establish a relationship before he takes her into a bunch of strangers. Not to mention he's never had her overnight (twice he's tried and rang me to pick her up because he couldn't settle her). Please tell me I'm being fair? I know he's legally got the right to but thinking about what's best for her.....