The parking lot where we wait for the school bus was recently paved and lines were painted. Ichabod didn't mind walking on the new pavement but he carefully stepped over the painted lines. I took him there daily and practiced walking across the lot, hoping he would overcome his reluctance to step on the lines. He did not. He told me that the lines looked 3D (as a deep crevice) to him and he really didn't want to risk stepping on them.
OK Ichabod, you can keep stepping over the lines!
Here is a video of Ichabod stepping over lines. Notice with all of my weaving in and out, I did "trick" him into accidentally stepping on a line with his back hoof a few times. At the end he was so focused on my husband with the camera he stepped right on a line. He was unaware of the mistakes and does not consider it proof of the safety of stepping on lines. Watch the video.