A few weeks ago, we wrote about check-in fraud. Also known as “fake check-ins,” this is the act of checking into a location — using Foursquare, Loopt, Gowalla or any number of quickly growing mobile check-in apps — when you’re not really there.

A lot of people (including me), do this just to mess around or game the system for badges and mayorships … not a big deal. But it could be an issue once these services begin to charge advertisers to run promotional campaigns that reward users for checking in to their locations.

This won’t be that big of a problem and there are lots of ways to battle check-in fraud. The most obvious is to place GPS-governed spatial limitations on check-ins (others outlined here). Foursquare has experimented with this and Gowalla has done it since the beginning.

This week, newer entrant ShopKick formed a partnership with Best Buy to offer a new take on these spatial limitations. It takes it a step further by only letting users check-in and access deals from within the store walls. To do this it doesn’t use GPS but separately installed hardware within Best Buy stores.

The way it works is users of ShopKick’s app receive a deal for a store location right when they walk in the door. To redeem it, they tell the cashier their phone number and the deal automatically registers. In the future they will drill down further to departmental deals within stores like Best Buy.

Though this requires more moving parts (partnership with the store), it could represent a new way of doing things in this quickly moving geolocation space. The backing of the store not only gives it more technical abilities, but also a fair amount of cross-promotional ability to get people to actually download and use the app.

It’s surprising that more big-box stores haven’t done this type of thing yet.  A few weeks ago, in fact,  we wrote about the retail sector’s overall lackluster performance in mobile adoption. Things like this should push the sector forward, based on competitive pressure, comfort levels and overall user demand.

Until then, you can check it out by downloading the  ShopKick app (which appears to be unavailable but coming soon) and cruising into your nearest Best Buy. Also check out the video (via TechCrunch) of the app in action at a San Francisco Best Buy location.