This is a bad mistake! In the second season of Star Trek: The Next Generation, there's an episode entitled, "Elementary My Dear Data" with a gigantic error. While Geordi and Data are on the holodeck talking with Moriarty, Moriarty draws a picture of the Enterprise on a piece of holodeck paper and hands it to Data. Data looks at it and astonished, he walks out of the holodeck with the paper! Holodeck material can't leave the holodeck!
[Actually, simple matter and objects can leave the holodeck. They are created using the same technology as the replicators. There are numerous cases where matter (paper, water, food) has left the holodeck, and this is accepted as part of the technology. Complex matter (i.e. people, animals, etc.) cannot leave the holodeck. When Data walks off with a piece of paper that Moriarty gave him, the system allowed those things to be carried out without recycling them. You can take issue with what makes the holodeck decide when to recycle material or not, but the fact is simple: some simple objects can be taken off of the holodeck.]