I think there are several distinctions to be made

1. A distinction between the people you are with
Some might understand, some others might not. With still some others (like the people in your workplace) it doesn't seem prudent to take the risk. There are others still, where you simply don't care, but that was not the question here.

2. A distinction between different levels of D/s
There might be a few very good friends (maybe even people into the lifestyle themselves) where one could show the full depth of the relationship e.g. I could get a spanking for being too forward.
There may be some other tolerant people where I might obey orders (like get drinks), but within limits so as not to overtax their tolerance.
There are people/situations where I might show my obedience and submission through signals or body language only He will understand.

3. A distinction between intentions
There may be a situation, where He might want to take me down a notch, by making me submit in public.

Generally the rule in my relationship was that, while we were in our apartment, my 'natural state' was subservient, while outside I was 'free'. However He could change that with a word or a nod. Both give me time off when we were alone, maybe because I had to work for my job or beacuse he wanted to discuss something serious with me, and to make me submit, when outside. I trusted him to know when it was best/right for me to submit.

Anne