When i met my (then)American girl friend at Heathrow on her first visit to UK I asked her to please NOT act like an American tourist.
She asked me what I meant and I simply said 'Remember what I asked'
One of the first places I took her was Windsor Castle.and as we walked
up towards the Castle proper a group of Americans were walking down.
She nudged me with her elbow and said'I see what you mean'
Americans are lovely people for the most part but sometimes are TOO touristy.If your neice acts like a civilised person she will have no problems. If she tries to come the 'We won two wars for you'and are
superior in all things she wont have such a good time.If she is a singer or a musician she will be very welcome in any Folk Club she might find.She will be equally welcome as a visiting audience.