As a guest you should always take a host/hostess gift. Wine, flowers, gadget for the kitchen or bar, homemade candy…it doesn’t matter but to watch people go to these dinners with nothing in hand, shows no respect for the host. It doesn’t need to be expensive, just thought out and thoughtful.
After watching an “expert” expound that you should always open wine a guest has brought to dinner, I want to assure you this is NOT the case.
As the Hostess, if you have planned your dinner carefully and picked the wine and it is chilling, then you just say thank you and put it aside.
In truth, once you give it to the hostess, it no longer YOURS and should be her option. If your wine is chilled, then perhaps this would be a good choice. If she decides otherwise, it is no ‘rejection’ of your gift.
I don’t understand why an ‘expert’ would want you to spoil your plans over this.