The interface means you have to actiuviely work to avoid these. When you add a new station it defaults to the same -name as the last one. This can be a useful speedup (edit the existing number) - but there should be something to tell you if you have entered two stations with the same -name.
This is already in the TODO list. It will be reported as therion error (in the plan and elevation projections).
Also because xtherion stays in 'insert point mode' until you cancel it, it is very easy to accidentaly put in a point somewhere random whilst moving the canvas, or to get two on top of each other.
This is already changed (will be in next release). If you will enter second point with the same type on the same place, it will not insert it, but it will cancel insert mode. Regards, S.