Answer:
Ouchy, certainly not good for the fellow is it? Ya they'd probably be disfellowshipped faster than the court system would convict him/her. No lengthy appeals with us. Anyway he'd be better off being disfellowshipped by us, than to sit in a cage behind bars like an animal. At least being disf he could attend our meetings. In the cage he'd be a lot more restricted.
And just like he could maybe be released from prison, we also reinstate a disfellowshipped person - - but only if we determine genuine repentance; which isn't dependent on some 'time served'.
Now I should add: there is an exception. It all depends what a country would determine as a 'felony'. In some lands we're put in prison for not joining the military. We have some JWs who still have a criminal record for that, even in America. So just being a 'felon' from the 'Law Standpoint' is not the criterion. We judge using the things in the Bible (God's Laws). So even such things as smoking, sex before marriage, adultery, homosexuality, etc could get them disfellowshipped; whereas the Law of the Land permits such things and doesn't call those things 'felonies'.