multiple terms in argument are always OR never AND

problem: under 'configure argument' -> 'Allow multiple terms per argument' the instruction reads "If selected, users can enter multiple arguments in the form of 1+2+3 or 1,2,3." which I take to mean that terms could be logically OR or logically AND, but a return value of 1+2+3 or 1,2,3 is always logically OR

steps to reproduce:

0) create two nodes of type Page with the titles "test 1" and "test 2"
1) create a new content type 'test_content_type'
2) give content type 'test_content_type' a nodereference field (integer field also is fine) 'your_field'
3) make the node reference field unlimited (or at least 2)
6) create a single node that nodereferences Page "test 1" only
7) create a view of type node
8) filter by content type 'test_content_type'
9) create an argument Content: your_field
10) provide default argument
11) fixed entry
12) Allow multiple arguments
13) try both x,y and x+y where x is the nid of page "test 1" and y is the nid of page "test 2". for example if these are the first two nodes you made, put 1+2 alternately with 1,2. for an integer field, the actual integers should be used.

if you're seeing what i'm seeing, your node of type 'test_content_type' always shows up even though sometimes it should not (because one of these operators should make it "AND has the field nodereferencing page test 2" which your node of type 'test_content_type' does not)

http://views.doc.logrus.com/handlers_8inc-source.html#l00790

i got this issue on views 2.8, views 2.11, and views 3 alpha3