Well I'm glad you're not on my friends-list then Campaigner...... 
Also, I'm not sure if these things have been 'patched-out' in the last few patches but it used to be that one could 'visit' a friends' city while they were offline and both use the bulldoze tool and also place parks! Needless to say I think that behavior is not as intended and if it hasn't yet, will soon be patched out.
