Wrapping a Pillar with Balloons
I would like to know how to do a balloon column using a column already in the room.ANSWER
Looks like they are using a technique called "EaSY System."
You tie an uninflated 260Q balloon (that's the long thin twisting balloons) around the pillar.
Then you create duplets using 5 inch (or 9 inch, depending on how large you want your balloons) round latex balloons.
Now you just slip the balloon duplets underneath the 260Q balloon, one duplet next to each other until you have circled round the pillar.
Do this circle by circle until the whole pillar is covered.
Here's a video showing the technique and some example designs:
There are also other methods for wrapping a pillar with balloons. I have written about those here