The more I think about it, having either the ISBN or DOI as default citationkey might make lots of sense too, if avoiding similar looking citekeys is the goal. That is also the best, if the bibtex database goes missing and users only have a backup of their latex file, because they then can very easily find the article.
JabRef has a nice duplicate detection feature and will indeed avoid duplicate citekeys, but when authors have similar names or there are multiple articles from the same year, sometimes the citekey can look very similar and albeit this should be very rare, some users of JabRef may by accident choose the wrong article.
Since this is my first post, I can’t understand the posting system(spam or vote) right now.
Sorry for my English level also.
My intension was making fall back options for duplication.
Maybe 2 options or possibly 3 options for avoiding “a”,“b”,“c”, although “a”,“b”,“c”, would be needed to avoid error.
As @ThiloteE says ISBN or DOI as citation key might good for avoiding duplication.
However author&year is kind of default rule in my area and It is really good with memory. Also, much harder gen key is not good with co-working. It seems not reasonable to give up such good option because of few duplication.
For those few duplication, if we can give another rules, it seems reasonable to me.