I ask this question(s) having read of incidents where airlines have been returned to the starting point because a passenger's name is 'similar' to one that is on the USA's no-fly list, although the person itself could be far far from the intended person, i.e. false positives, mistaken identities.
Specifically, I am interested in the effect on a third country national, who is legally resident in the UK or for that matter in another EU member state.
What happens if somebody's name does match on the list, although the person itself is far from the intended suspect? E.g. John Smith, James Smith are available by millions of dozens. Can the person return to his country of residence, i.e. the UK or the EU member state? Or will the person be forcefully be returned back to the country of origin?
Of course, I can understand the most recent case of KLM, where the 2 passengers did seem have a record. But what about other cases that have been in the news, e.g. BA 175 and other popular case is Mr. Stevens (Cat Stevens)? Of course, Mr. Stevens was a EU national - the persons have been EU citizens, thus allowed to return to their country of residence / origin.
In other words, what I am trying to subtly ask above, in accordance the handle that I am using ("compulsive worrier"): WHAT IF, "a" passenger, who is a third country national, legally and permanently resident in an EU member state, with a name that is similar to a name on the no-fly list (but is not the intended person), is allowed to board, but in due course the flight is returned to the starting point, does that passenger, without further review, lose his right to reside in that EU member state, based on suspicion and stigma of being a terrorist?
Would a mere suspicion of the passenger being a criminal and being tagged so by the US, cause the passenger to lose his residence in a state where he is legally resident, assuming no fault or error on his/her side.
Well, no, I've never had problems of any sort. But that is exactly why I posted under the handle "compulsiveworrier",
based on me actually imagining the worst case scenario. 
Thanks. Any views would be appreciated, especially substantiated, knowledgeable ones.
Thanks once again. Any feedback would be appreciated.