Some burners (Liteon, NEC and Ricoh) can change the booktype of a DVD + to DVD ROM booktype. This is the same as a commercial DVD.
It means it will allow a DVD player that doesn't play DVD + to play it as it thinks it is a commercial DVD. My Panasonic DVD Recorder works like that.
A DVD+RW can be chnaged after burning but a +R needs to be done prior to finalising.