This guy carried his handgun loosely in a mesh vest. There may have been a Velcro retention strap, but the observer could not tell. We are unable to tell if the gun is in a cross-draw style or if the carrier is carrying it on his left (whatever his dominant hand is).
If you are going to carry cross-draw, do not do it as an inexperienced carrier using poor gear. A cross-draw from a loose vest/holster will tend to pull the material of the vest with the gun as the carrier draws it. Cross-draw requires practice and (particularly by amateurs) bringing the gun on target will sweep everything to the side. A strong-side draw keeps the muzzle down, or in the general direction of the target prior to proper aim being taken.
A holster that is snug to the body makes it more difficult for it to be snatched, easier to feel if someone is trying to grab your weapon, and makes retention easier.
Don't: carry losely; don't carry on your weak side, use better retention
Clayton E. Cramer
Gun Free Zone
The War on Guns
The View From Out West