The governments job is to govern, not to check who is sticking what where with who.
For the legal recent migrants, they know they will/are being swamped by the illegals - the maths is simple, and the illegals if 'welcomed' will be unending. The right answer has to be rules on coming, returns, plus foreign aid of a real help, like roads to access farm land, to grow crops for both local and export. Helps everyone. Giving everyone a hotel room in NY isnt helping. Same for London etc.