Both the cases you describe are in breach of the rules - the minimum distance between controls is 25m (it used to be 15).
Similar features within 30m (60m in forest) is a guideline rather than a rule. The one time I sat on an IOF jury dealing with a case of this type, we decided that an organiser breach of a rule can potentially lead to a reinstatement, but an organiser breach of a guideline would not.
Know how it can happen at a championship, having overlooked a control separation as event adviser at a Victorian Championship. Its easy to do. You have so many issues swirling around in your head. After a mispunch result, I paced out the distance and it was right on the 15. Too close for comfort. But given that and the fact they were on different features, the mp remained. Maps are not always true to scale, and what might pass the distance test using software may not be the case on the ground. This is particularly likely to be a problem in sprint where significant exaggeration is required to make the map legible in areas with closely spaced buildings.