Using the dispenser mechanics, I've created a simple tamper-proof dispenser which could also be used in Survival maps or SMP. As dispensers trigger every time Redstone in their range update, you can't destroy any blocks of this creation in order to empty the dispenser before it triggers.

Texture pack by HoneyballLP:
dein-infotext.blogspot.de/p/texturen-pack.html

Royalty free music by Kevin Macleod:

incompetech.com/

My Youtube-channel:

www.youtube.com/user/SSBreloom