Of course some @holes will demand way more than the true value; that's why a standard has to be set. I can see the attorney ads in border states now..."Is the Federal Government trying to steal your land for the wall? We can get you more! Call today!"
Head those time consuming and costly suits off at the pass, with fair rules about payment.
I have seen eminent domain in action. My client, an old country attorney, had a portion of his business property taken for a road widening project. The land is not in question. The government gets it if they can show it is for a government use, (Kelo was not law then). The only issue in court was the value of the property. The government always low balls it. The landowner, in this case the attorney, has to show that the loss of use of the property is more than the government’s appraisal. In the attorney’s case, he was able to show plans that he had taken steps on to build a commercial office building which justified his demand for thousands of dollars more for loss of future income.