What is the bbox of an incomplete OSM primitive?

[GerdP]

I stumbled over this while analysing performance problems in the
QuadBuckets.search(BBox searchBbox) method.

I noticed that incomplete primitives have quite confusing bboxes:
1) an incomplete node has
xmin = xmax = ymin = ymax = 0;
2) an incomplete way has

xmin = Double.POSITIVE_INFINITY
xmax = Double.NEGATIVE_INFINITY
ymin = Double.POSITIVE_INFINITY
ymax = Double.NEGATIVE_INFINITY

if all nodes are incomplete, else it will
be the bbox of the complete node(s).
3) a relation with eg. just two node members
where one is complete at (10,40) and the other
is incomplete will span a huge area from

xmin = 0
xmax = 40
ymin = 0
ymax = 10

I would expect that the bbox of a relation is only
calculated using the complete nodes.

I'd also prefer when the bbox of incomplete nodes would not be located
at (0,0), but I assume that there are good reasons for this.