Daniel Kahn Gillmor:
Yet surely there are some user-wide services that don't need DISPLAY at all, and would be happy to run per-user?
GNOME Terminal isn't one of them. Witness the behaviour of gnome-terminal-server run as a service if it doesn't have a DISPLAY environment variable:
@40000000584830f10ae09b9b Unable to init server: Could not connect: Connection refused @40000000584830f10ae0dbb8 Failed to parse arguments: Cannot open display: