What qualifies as useful but incomplete data is relative (and to a degree -- a matter of opinion). If am told "there is a big mountain here, give-or-take 1 km"

What qualifies as useful but incomplete data is relative (and to a degree -- a matter of opinion). If am told "there is a big mountain here, give-or-take 1 km" that's probably useful. But if I'm told "there is a water fountain here give-or-take 1 km" that is pretty darn useless. Your data is probably not near as bad as that, but if you put a POI on a map, and somebody goes there, but doesn't find it because its a couple hundred metres away, they're going to assume that it moved/went out of business (and remove the data). I can think of two ways around this. One is to make a note about the incomplete data you have and hope that somebody finds the actual location and adds it. The second is to go-ahead and add the thing with a "fixme" tag saying "location approximate" or something. I've seen both techniques used in the past.