As an OSM contributor in the UK myself and my peers only use clean-room data ( firsthand visit ) or data from public sources ( planning applications etc )
Google says it is[0]. It might be true because when you get street address from Google, you are also getting the mark on the map for the location. Whether it's true legally or not, it's better to stay away from their data. That is, if you use Google maps, you agree their terms and thus you are not allowed to copy the data.
And btw, I have seen (possibly deliberate) mistakes in street address markers in Bing maps (which is the recommended map[1] to follow for Open street map editors). So don't think that they won't find you if you copy their data).
[0] https://developers.google.com/maps/terms#6-googles-proprieta... (The definition of Content is explained in the following section, which says "... and places data (including business listings). ")
Microsoft has generously provided permission and server resources for use of Bing Aerial Imagery since 2010, but that's different than their map product.
Lately there's a bunch more imagery providers that give permission for use in OSM. Mapbox, Digital Globe and ESRI all provide imagery layers with global coverage. There's also quite some government imagery available, OSM editors will show them as an option in the areas they cover, so be sure to check when editing.
I don't know whether Bing Maps uses trap streets [1] or not.
OSM is not a place to explore the grey areas of international copyright law.