No one realized that the player don't really need to enter the premise to access the Gym or PokeStop?

There's a radius to it, to prevent people from simply trespassing private properties. Unless due to some agreement, it's heavily shrunk to fit the business premise only. Or else just standing in front the shop or enter the neighbor's shop is sufficient already.

What I foresee is Pokemon Go selling spawn events to malls. E.g. 1U, Mid Valley, Pyramid etc pays Pokemon Go for a rare pokemon to spawn in their mall for a weekend or so. That & combined with some marketing would definitely drive people into the mall. Another possibility is to sell battle events (a feature not introduced yet), e.g. spawn an evil Charizard for an hour in specific place for people to battle in masses.

Cheers! I did the same thing, just went into McD....leech their WiFi & air-cond for free for few hours & then chao LOL.

That'll probably one of the main income for Pokemon Go. Selling "events" to big companies as crowd puller. Set an event date, blast kau kau in the media that there'll be a Mewtwo spawning at 12pm to 4pm in Genting for 1 weekend. Damn that mountain is gonna be so crowded.