I would like to see a discussion of the right way to fix the import and export issue. The following is only a stop gap but may be better than nothing, but may be easy and at least plug some holes. What about changing export to not do the write if the file already exists. At least that stops over-writing exising database and property files. Adding new database files does not do much as the system has to find them in existing system catalogs.
Does not solve creating a new property file where one did not exist.
Does not solve creating new recovery log files with just the right name and crashing the system to get it to use those files.
Also may create an upward incompatibility where we use to allow overwrite. We certainly don't document that we allow that. Seems like most would not complain if we gave a reasonable error message saying export failed because a file with that name already existed, and to delete the file and retry the export.