As I am 6' 1" in bare feet (I think I've lost a good 0.5" with age!), I can only say from experience that I think being tall cuts both ways. Yes, a tall man (but not necessarily burly or muscular with it) is likely to be treated by most people with a little more caution if abuse or other aggression is in the air. But it can also make him a target, both in the sense of being more visible and also because he might be seen as a challenge by some cocky bloke who fancies his chances with 'lofty'. On the very few occasions that I have been threatened or mildly assaulted, it has been by a noticeably shorter bloke with 'attitude'. On one occasion, Mr Shorthouse was accompanied by his girlfriend/wife (but no boots or cake involved) - it was just a case of pushing past me in a doorway whilst he was leaving a shop, and not liking the rebuke I dared to utter. He turned round, raised his fists and likened me to something essentially feminine - but seeing my stance (if not size) and that there were several interested witnesses, thought better of it and skulked off.
I haven't (yet) experienced any problems whilst wearing heels. Their extra height is not really needed in my case; their potential for limiting swift and nimble movement might be an issue. The nearest I have come to experiencing grief was missing my footing whilst descending three or four wide steps as I entered a pub/restaurant, whilst wearing my 5" MJ boots. My tumble was noticed by three hairy apes sitting just inside the pub, who thought it most amusing, but I don't think my boots were spotted and I merely grinned back and picked myself up before walking (mincing?) in carefully.