prevent people from using a modified local swf

[Musika]

Hi,

Example, I have file (original) who it loads on a page: www.mysite.com/blabla.swf

Some people use software this great software to load a modified local to cheat.
I would like to prevent people from using a modified local .
Do you think that this code will solve the problem?
1) create a condition in the : /blabla.swf shows the content of blabla.php
blabla.php :

header("Cache-Control: no-cache, must-revalidate, no-store\nPragma: no-cache\n");
header("Content-type: application/x-shockwave-flash");
readfile("blabla_secure.swf");