I'm not sure there is a great way to protect it, and based on my experience it is a Crud shoot.
For mine, the bobcat driving over it during the excavation didnt bother it at all. Just when I thought I was safe, the plumbers got it when they plumbed to the sewer line for backwashing. It was really unavoidable since they had to trench from the equipment pad to the front of the house.
Once it was cut, I called at&t and they ran a new above ground temporary cable. They marked it well and routed it so that it would be out of their way. They just buried the permanent one this week, so hopefully nothing gets it again in our final few weeks.
Also, while the hundred passes of the bobcat over my line didnt cut the cable, the cleanup crew brought a bobcat a few weeks later. They took 1 trip in and out of the backyard, but had to go about 6 inches into my neighbors property to avoid the plumbing and that 1 trip killed their line.
Good luck. I would bet on it cutting your line and keep their phone number handy.
Edit - The site software didnt like my original saying, and changed it to "crud shoot". Funny stuff.