I'm not sure if this is what you were after but I have some OO documents which have some sections with checkboxes and others without. The only downside is the space for the checkbox is still taken up even though the check box isn't showing.
The document needs to have them showing by default, which you can enable via the View menu if they are disabled. Then for the sections or rows you don't want to have them you can disabled them within the document on a line by line or section basis. To turn the checkboxes off, first you need to select the section or row and then right click on it and from the pop up menu select Set Status and then choose NONE.
if you save the OO file by exporting to an OPML file you can view the way its done in OPML by viewing the resultant file in textedit.