Lineholders just have to "inform" crew scheduling that they will be deviating from the DH. Reserves must ask permission.
Cadetdrivr, you are probably correct in that this little gem will probably not be received well by our European commuters. They will now have to bid trips to their hometowns and commute to EWR/IAD to start their trips. Hopefully nobody will try to commute the day of....that would make for a long day.