Ok, since this isn't on You Tube, I can put the player in the this thread. I found an Invisible Fence on Foundry. See the invisible fence video on GeeVee
Yeah, there are a few of those in Foundry. There is one under the platforms in the bases, but there is enough room for a spartan or two from the fence to the invisible fence.
Yea this is old news, we found this within like one hour the first day Foundry came out. I'm actually surprised that no one has used them as a jail of some sorts in a map yet.