Well who thought that was going to happen? Donald J Trump is President elect of the United States of America. There is now the question of how many of his pronouncements made in the heat of the election he really intends to implement. Some will of course disappear into the ether. For example I can't actually imagine Hillary Clinton being locked up, even though some disaffected US citizens may like to see that happen. The famous proposed wall between the US and Mexico is going to be tricky as well.
The one thing that does remain as a major issue to be resolved on both sides of the Atlantic and across Europe is illgal immigration. There are millions of illegal immigrants in the US and many thousands in the UK. What is clear is that fence or no fence, English Channel or no Channel, it's pretty much impossible to keep out determined and sometimes desperate people from moving across borders. The areas to patrol are far too large and even if you could blockade entry points successfully, that doesn't solve the issues of visa overstayers or other legal entrants who become illegal, including those who use false passports and visas.
Pressure will be brought to bear which will make it more difficult for illegal immigrants to work. And it stands to reason that governments will look to push more of the responsibility for checks onto employers.
As a business are you prepared for this? Can you honestly say you understand and check passports, visas and rights to work? Do you have a system to ensure sub-contractors do the same? If you have a system in place does it remind you when visas and documents expire and a staff member ceases to have a right to work in the UK.
You can expect government action to tighten these rules. Don't get caught employing illegal immigrants. The fines are huge and doing it knowingly can result in a prison sentence for you - the employer.
Think of that when you are setting out your personnel security requirements. Think of the £20,000 fine for each illegal worker when you are accrediting staff at your events. Think of the security risks of employing criminals in key roles in your business. Think of that when you are considering whether staff should be accredited when working for you. Make personnel security a priority.