In the referenced message, Jared Mauch said:
You may want to consider using tftp/rcp/whatnot loaded files for this.
As it loads [most if not all depending on the config length] all of the config then parses it promptly.
this will prevent leakage in rare cases.
- jared
I have noted that even tftp-loaded files run the risk of a BGP scan occuring between the parsing of "no access-list foo" and the parsing of the first "access-list foo" line. It appears Brand C takes the non-existance of an access-list to mean "implicit permit". I think this is probably the source of much of the seen mini-leaks. As someone else mentioned, prefix-lists (again brand C) do allow for insertion and deletion of individual items at "any" point in the list, so may be a good workaround. However, if you are doing anything at all "interesting" in your acls, it becomes a lot more difficult to translate over to prefix-lists. One major item that seems missing is the ability to match less-specifics. There are certain instances when this would be really nifty. Brand C extended acls, and Brand J prefix-lists seem to be able to partially cover this, but not perfectly.