Using the enclosure relation to let the player drop things which he only indirectly carries.

By default, Inform only lets the player drop those things which he is carrying – that is, those directly in his possession. Things inside satchels or on portable trays have to be taken first.

If we want to change this behavior, we might add a dropping rule that distinguishes between carrying and mere enclosure (introduced back in "The location of something" in the chapter on Things):

"Celadon"
The Tea Room is a room. The player carries a black lacquer tray. The lacquer tray is portable. On the lacquer tray are a celadon teapot and a napkin.
Before dropping something:
   if the player does not carry the noun and the player encloses the noun:
      say "(first taking [the noun] from [the holder of the noun])[command clarification break]";
      silently try taking the noun;
      if the player does not carry the noun, stop the action.
Instead of taking the napkin:
   say "It seems to be stuck to the tray, possibly by an underlying wad of gum."
Test me with "i / drop teapot / i / look / drop teapot / drop napkin / i / drop tray".
Test me with "i / drop teapot / i / look / drop teapot / drop napkin / i / drop tray".
Tea Room

>(Testing.)

>[1] i
You are carrying:
a black lacquer tray
a celadon teapot
a napkin

>[2] drop teapot
(first taking the celadon teapot from the black lacquer tray)
Dropped.

>[3] i
You are carrying:
a black lacquer tray
a napkin

>[4] look
Tea Room
You can see a celadon teapot here.

>[5] drop teapot
The celadon teapot is already here.

>[6] drop napkin
(first taking the napkin from the black lacquer tray)
It seems to be stuck to the tray, possibly by an underlying wad of gum.

>[7] i
You are carrying:
a black lacquer tray
a napkin

>[8] drop tray
Dropped.