Boost Module - Delete file or truncate file size to 0?

Have another idea for the boost module, use the -s flag instead of -f in RewriteCond.
http://httpd.apache.org/docs/trunk/mod/mod_rewrite.html#rewritecond
Then boost doesn't delete the file it just ftruncate() it when clearing the cache. Don't know how or what this would help with, other then possibly being nice to the file system. Switching the rules to use -s instead of -f would also act as another sanity check. Would this be worth it to do? Would there be any real benefit to not deleting the file, just setting the size to 0, when it's cache lifetime is up? Would there be any negatives to doing this?