Situation: When you place a .zip file into a map folder and call it "resources", you are placing a resource pack into a map, and nothing can go over those textures (as far as im aware).

Here is the issue: When you try this for a vanilla server, it does not work.
The pack is not shown even though the map has it inside of it, forcing it instead of asking if players want it (using JUST the faithful x32 font in the pack, all other textures were deleted.)

Links:
http://imgur.com/lEGiHfM (single player world folder and resource pack .zip)

http://imgur.com/MZ6Rmk8 (pack from ingame singleplayer 1.8.3)

http://imgur.com/1JT0ycV (the same exact resource .zip in the server folder)

http://imgur.com/QbPa3H8 (pack from on the server that is being hosted using the deafult vanilla server 1.8.3)

http://www.mediafire.com/download/0s39h8zkmbrisci Texturepack .zip used

76.119.232.218:25565 Server used to test the pack (yes it is public)