Here's the list of what I do carry when the list of prohibited items is long.

Keyholder (CtyComm 6" ss cable)

car and house keys
Arc Light AAA LED flashilight
Spare AAA battery
ResQme tool
ETS low profile whistle
Pico Pen
Swiss Tech screwdriver set (can't remember the official name)
small SS lighter (again CtyComm)
Photon-like squeeze LED light

I also carry Verizon Smartphone, an ASUS netbook with wireless modem, a small rechargeable Lithium battery pack that re-charges my phone and spare car keys. I use a small CC MPCC case to carry a small FAK, some antacids, pain killers and hand sanitizer.

Leaving a locked case at the front desk is not an option. I'm not too worried about defensive tools, that's what the guys with guns are for. Plus I haven't thrown a punch in anger in about 50 years.

What I leave at home is all the extra stuff that makes me less dependent on others in a "real world event". Bigger FAK with trauma kit, water storage/purification, bigger flashilights, additional tools, etc. So, if they want me to leave all that stuff home, if something happens I'm going to be looking around for help from them.