If Trump gets elected, they may regret having said “NO”, he has a way of winning. My guess there might be a stop of money transfers out of the country (one of the main reasons the illegals come her is to send money back to their homes). Trump may have numerous other avenues to explore that will “hurt” the Mexican gubmint. Best no upset the Donald and payback can be pretty severe, the cost of that wall may turn out to be peanuts.
A president Trump should put a border fence surcharge of 10% on all money transfers to Mexico. This will pay for a fence. All the while he should be loudly blaming the thieving government of Mexico for this surcharge. Turn the Mexicans against their Federale gov’t