option to force players into spectator mode when they use /tp to teleport to a player

[felix920506]

An option to automatically switch players into spectator mode when they use /tp to teleport would be great. it would not disturb whomever is the target.
How I would like it to work:
/tp x y z, tp player x y z will stay the same while /tp player will switch the person who issued the command to spectator mode when used

[Chew]

Whilst a good suggestion, this seems like something better suited for a plugin using the Essentials (or, hell, even just the Bukkit) API.