SCT Controller described a confused arrival procedure event prompted by a Data Block indicator that was inaccurate; the reporter suggesting the discontinuation of the problematic procedure until briefings and a proper fix can be completed.

Narrative

The B737 was at 110. His Data Block had a trailing R; which is supposed to indicate the aircraft is on an RNAV SID; in this case the CEEME1 arrival. All the B737 aircraft are supposed to be on the FERNANDO5 arrival; due to an equipment issue with their fleet. When I inquired as to which arrival the B737 was on; the pilot replied the FERNANDO5 and that they were issued 'a screwed up routing to get there'. I reported the anomaly to my FLM; who contacted ZLA. The response was 'The B737 cannot get rid of the trailing R and ZLA will not remove it either. The SCT Controllers will need to verify that the B737 aircraft have the appropriate arrival. A bad situation gets worse with the CEEME1 arrival. We now have aircraft tagged with one arrival; but on another arrival; but we also need to verify which arrival they actually are on. Discontinue use of the CEEME1 arrival until it can be properly designed and all controllers and pilots are properly briefed on the procedure. It has been nothing but problems from the day it was turned on.