I've been dealing with the same issue; I'm not sure it's quite a safe as "relax" though :)
Two concerns I'm investigating:
1) It seems wrong to me that LVL reports this an application error rather than a license violation. So be careful how you treat this in your policy, google's sample code implies that an app error is a developer error and is something your should either fix, or at least not penalize the user for. However if you ignore this in production builds it may provide a way for a hacker to disable your licensing by altering the app version to > the released version. (I don't know how feasible this hack is, but I have run into all kinds of crazy hacks already in CN so it wouldn't surprise me)
2) As pointed out some other threads e.g. Android "Not_Market_Managed" error this creates a problem when publishing new builds. I have not yet been able to make this turn off by saving a draft apk into gplay, so if I actually have to publish to turn this off that would be bad news as there's no way to test this without releasing.
The strange thing is I do not always get this error with new dev builds. Another post speculated that LVL has some rule like you can be +1 over the published version code without triggering it. I hit this error when I had done two released quite close to each other; maybe they are right?