>>SYS(2015) is not safe either, SUBSTR(SYS(2015)3) is safe AFAIK.
>
>Why?

From help on SYS(3) in VFP8: "SYS(3) may return a non-unique name when issued successively on a fast computer. Use SUBSTR(SYS(2015), 3) to create unique, legal eight character file name." This line has been removed in help for VFP9, so I guess it's simply an old habit.