There are half a dozen Plugins already that deal with L4D Survivor Upgrades one way or another. Thanks to all of them, i think Fyren originally enabled it all with his l4d_mmo plugin.
This here is different ... it won't give anyone anything by default and remain silent. It will also not litter your Admin Menu.
It does however give users the sm_laseron, sm_laseroff or, simpler, the toggle command sm_laser for the Laser Sights. It also blocks the dumb "expired" messages when turning Lasers off.
Additionally, it won't break your MOTD and/or other ingame Webpages.
For installation put the .smx in your plugins folder.
Configuration:
l4d2_lasersight_delay (default 10.0) - How long do the commands 'cool down'
Changelog L4D:
1.0.0 - Release
1.0.1 - Now sets Survivor_Upgrades 1 by itself
1.0.2 - Major Code Screwup breaking sm_laser toggle fixed
1.0.3 - Removes Upgrades on Round end to prevent eerie things from happening
1.0.4 - Minor Bugfixing
1.0.5 - No more gamedata file needed. Unloads itself if not in versus mode
1.0.6 - updated Signatures, added Sig error logging.
1.0.7 - Linux byte Signatures (WTF)
1.0.8 - reverted to gamedata file (l4dlasersights.txt into gamedata!)
Changelog L4D2:
1.0.0 - Release
1.0.1 - fixed tiny Callback bug
1.0.2 - added command cooldown and convar
Note the Laser has actual gameplay value in L4D2 - it increases your weapons accuracy.