Jheshka: Screenshot with random number printed on it? What is it good for? Any player could do that ... make a snapshot of them with a number on screen and so falsificate the proof. I would use some kind of checksum algorithm (let's say CRC32), or hash (MD5) of combination of player's name and/or IP address and/or date and so on. So it will be completely back traceable. You could take screenshot, look at the number, put it through the algorithm and say "this is false/true".
And how to you propose to create an md5 algoithim in an amxx plugin?