Which has happened more than once thanks to the leeway already given to those who manage and enforce the no fly list. Now that right there isn't a complete block for getting back into the country but enough that your average citizen can't afford to return via other methods. Now imagine that level of headache and inconvenience at every aspect of your life, all the way down to not being able to pay your dog walker because your dogs name is Dash, and thats too similar to Daesh.
More leeway is the LAST thing law enforcement in this country needs. For someone who hates big government you sure do love trying to use it to fuck over others who aren't like you.