[Simon Logic]

Nice plugin.

I suggest moving on-ground check from lie_flat() into fw_touch() right before checking by classname (& reading the classname of weapon) because it is much faster in most cases. Also you can improve plugin by introducing a check with "item_" (so matching at least first 5 letters) instead of full named "item_thighpack". So you'll cover a hole class of items, e.g.:
item_healthkit
item_thighpack
item_longjump
item_battery
& may be others...

Plus you may add one more check against "armoury_entity" classname.

Also you may ignore any weapon id equal or less than get_maxplayers().