Step 7: Like a Boss
The last place they're going to want to look is underneath your cooler, and even if they did, it will take the trained eye of someone making more than $12/hr to see the seal now that you've gently scuffed the bottom up a bit on the walk to the gates.
Find you and your friends a spot to set up camp. Get out your chairs and blankets and sunblock. Get comfy, you're going to be there all day.
...and when the mood strikes, get a friend to help you lift the cooler up and have another person use a car key to pop the bottom open. Your cooler will pay out like a slot machine and everyone sitting around you will probably get a lot friendlier. But hey, you have a whole handle to drink, what's the rush?