People would have a reasonable expectation that, once the proper "accented" version becomes available, people having registered the non-accented version would have priority in getting it. (Actually, the original expectation was that a variants system would be developed for accented Latin characters, so to avoid the problem altogether.)
However, no one at ICANN seemed interested in the issue - actually, no one even seemed to understand it.
You might want to take a look at the IDN policy tables at http://www.iana.org/domains/idn-tables/. Domains are encouraged (perhaps required for ICANN contracted TLDs, I haven't looked at the contracts lately) to publish the list of languages and character sets in which they accept registrations, and the rules for each language. Look, for example, at the rules for .BR which specifically say that they will not accept names that differ only in accents. There's information for several European countries, but I am surprised to see nothing from .LU. Regards, John Levine, johnl@iecc.com, Primary Perpetrator of "The Internet for Dummies", Information Superhighwayman wanna-be, http://www.johnlevine.com, ex-Mayor "More Wiener schnitzel, please", said Tom, revealingly.