Copenhagen trip - locking brompton outside or leave at home?

My partner and I just bought Bromptons for travel and are planning to take them to Copenhagen this summer. We will be getting an airbnb and using them to get around. There will definitely be places we can't bring a bike in (i.e. Tivoli gardens, museums, etc). Do you think it's safe to lock them up given how many people have bikes there (so they will probably be one among hundreds) or should we leave them at home and take public transport?