I am sorry that the thread about this subject ran a bit out of hand and that it is closed now. I hope it is OK to add some comment.
OOwriter provides a button which is called "insert unnumbered entry" which does exactly what is expected: it inserts a blank line in a bulleted or numbered list. I am surprised no one else saw that

. I didn't even know it myself, so I could not contribute to the original thread. But as I was editing a document where I had to insert non bulleted comment in the list I suddenly saw this button. It is in the floating toolbar which pops up when editing in a bulleted list.
Note that it is logical to insert empty lines afterwards. There is no way Writer can know not to bullet a line when you press enter. OK, it could remove the bullet at the second enter at the empty line, but then the decision is whether to continue bulleting or not. (I think it is the standard behaviour of Writer to remove the bullet in such a case) But then you have lost your list and have to tell Writer again to bullet. It is impossible to solve unless Writer can read minds. The "insert empty line" is an elegant solution IMHO
jlinkels