If someone tries to start with "rest" or "jsonp" and there is no http support this should be an error and the system should fail to start with an appropriate error message. Currently these options are silently "ignored" (from the users perspective).
The other option would be to turn on the http interface if dependent options are specified, like is done with auth/authKey.
EDITED TO ADD: Also produce warning is -
rest/-jsonp is overriden by --nohttpinterface