A manually entered path in the path field, can override / hide another node, if you enter the other node's node/# in as the path.
For example, say you create node/7088 as a test page... then you create node/7089 as a 2nd test page, only this time you enter node/7088 in the path. You will no longer be able to pull up the original page, unless you change the path in the 2nd page to something else. I can't think of any use case for this... At the very least, it should give a warning that the path already exists for another node...
Not sure if it works this way in Drupal 7 or not, I will test it out and report back.
Comments
Comment #1
mstef CreditAttribution: mstef commentedThis exists beyond nodes.
You can create a node and make the path "admin" and your admin section is now that node..
Comment #2
mstef CreditAttribution: mstef commentedComment #3
Dave ReidMerging this issue into #121362: Do not allow existing or reserved paths as aliases