No I don't think you are at all unreasonable to feel uncomfortable about how plans were changed without your involvement. You are of course concerned for your (v young ) daughter's welfare. Quite right too.
Some parents are very cavalier about play dates, others are cautious. I think you should feel that you can turn them down or ask at least feel you can be open about your concerns. She is your child and ultimately it is your grief if something happens to her that you may have been able to prevent.
I approach play dates from the viewpoint that parents may feel like me, that is, concerned for their child's wellbeing. I let them know who will do pick up, who will be watching them, what they ate and, for sleepovers, when they went to sleep.
My ex offers play dates but cautiously and the parents know it's fine to say if they'd prefer their child visited at my house only. It isn't that they suspect my ex is a paedophile, they just feel more comfortable because I've had more contact with the child/mother. He is fine with this, he works in a part of social services and totally gets child safety issues.
Likewise, we would speak up if we were unsure about an arrqngemnt. We turned down a ride for dd to travel with another child's dad to their holiday house because my dd said it would be weird going only with the dad and not her friend or mum (they'd already gone) We were quite open about it and everyone laughed.
I also expect to be informed if they visit others while at friends and if others visit them.
These cautionary measures are based on my own experiences during childhood and my experiences as a news reporter. It doesn't matter whether they seem over the top to anyone else, they are what is right for me.