So, I played a game just now and for the first time ever, the people on my team decided to hide my items in the corner of the forest.

I found out because I looked at the replay.

I find this extremely disruptive in creating a cohesive gaming environment.

What I would like to suggest is adding an additional function of the ALT key that allows the player to find on the map, any items that has been dropped, if any.
The items revealed must specifically be owned by that particular player.

Eg.

Player B controls the courier and drops the item of Player A on the Radiant safe lane treeline just beside the racks.
Player A would be able to find out where his item has been dropped by pressing the ALT key. If item has not been dropped, nothing will appear.