Yes I don't believe complete strangers besides psych trained EMTS or ER staff has ever asked us about our "dissociation" before.. But from my experiences dealing with random (non psych/ health related )strangers who notice something "off". I very had a few different types,of experiences.
1. The stranger who insists they know me. May or may not call me by another name. If they just are certain they know me from somewhere (no name)...then just act like IDK, just must have one of those faces or familiar strangers, maybe we have crossed paths on transit schedules etc... If they call by name, then either that part will come forward and talk to them if they want to...or I just say I'm sorry you must be mistaken me for someone else. If they press I'll show them our license...
2. Acting oddly in public place. Someone asks if we're alright or OK or need to call someone..this happens sometimes if scared child parts get triggered suddenly or if talking out loud or if gone "catatonic repeating flashback state" or if "come to disoriented by unfamiliar surroundings/people.

If we're talking out loud. We just try to laugh it off as absentmindedness...and sometimes it is just that.

If we've made a scene. We either just walk away quickly find a place to "hide" until we can calm down.

Scared child usually either another part such as myself will snap to asap when spoken to by a stranger. I'm a protector and strangers=danger. My response is generally a huffy I'm fine and walk off like nothing happened. Otherwise, if for whatever reason child part does not vacate. We carry soothing objects. Drawing pads crayons small toys. Scared child parts will generally try to hide/self soothe until help arrives either in form of a "big part" or call from a known trusted person. ie Hubbie, BFF, even family member possibly..tho that's not usually ideal.

Catatonic states..are well catatonic no one is gonna respond til they pass. Gotten sent to the hospital for that a couple of times.
Disoriented in Strange surroundings..ask someone where we are. Try to appear lost..well we are lost so not hard. If people question more or we still are confused..either ask where nearest cabstand or train is....or in extreme circumstances just act drunk (not proud, but I've had to do it before)

Disoriented surrounded by strange people. Usually make an excuse and get the heck outta there! Like excuse me I need to make a call or go to the restroom etc...figure the rest out after.

Oddly enough, people we know are most likely to brush off our "weirdness"..lost some friends to this disorder unfortunately. ..but mostly they just see a sudden "mood or attitude flip" and depending they either ignore it or just walk away/hang up. Even family makes up their own reasoning for our "off behavior" ...unfortunately a lot of them think we are addicts or junkies..been accused many times and it hurts...because I almost never even drink, especially since realizing the added and unpredictable effects substances have on us. I try to keep a very clear head.

But I be said it before and I'll say it again! This disorder is a blessing in the fact that most people can not even fathom it's existence...which leads to them finding a more personally understandable rationalization for whatever comes out of us. This in its self is another layer of protection we are afforded.