If there are no fire sources near the car with plywood, then it is not considered hazardous. However, if you have a problem with the car being there or if you think it might be risky, then you can request your landlord to get rid of the plywood or maybe park the car in a less risky way for safety purposes.
No hazard exist here just a heck of an inconvenience. Prepare for lock out ahead of time by hiding a key or better yet--do what we did-- we installed a push button combo lock. If locked inside the garage we just push out combination +*+* and the door opens. Purchased at Home Depot.