Classic car alarm systems?

Need an anchor point cemented into a pier/pile in driveway.big big chain and padlock around rear diff. A royal pain in the ***, but consider what happens if its stolen.
You are very fortunate you saw them,too bad you couldnt get a plate or id the purps.

There’s a truck touring around here scoping for snowmobiles,my old buddy has seen it a couple times. Positive its someone up to no good, as they take off if someone spots them.