As a convenience to scripters and to speed up reads and writes to files, I would recommend that mIRC keep file handles open until a script alias, event or thread completes. This would in effect give scripts that use $read() and /write all the benefits of /fopen without the tedious nature of /fseek, $fread, and /fwrite.
It would not be unusual for mIRC to keep a file handle open until a script thread completes its task (or errors out).
Well. At least I won lunch.
Good philosophy, see good in bad, I like!