Depends.

qwurx [shmem] ~> touch foo.txt
qwurx [shmem] ~> perl -Mautodie=open,unlink -le '$_=pop;open "<", $_; 
+unlink $_' foo.txt
qwurx [shmem] ~> ls foo.txt
ls: cannot access foo.txt: No such file or directory
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AFAIK...

• Linux: Unlinking a file doesn't break the relation between an open file handle and the file system space allocated for the file; nor does holding an open file handle prevent unlink from succeeding, which is a directory related operation. The file's blocks are open to reallocation after the last reference to the file container is gone
• Windows: Can't delete a busy file (the OS is aware of open file handles pointing to it)

Depends....

Yes, there exist differences between the platforms

And yes, the portable practice is preferable because it is portable

And yes, error checking will let you know if there are errors