At some units the ILS can be intercepted but if a descent was taken it would take the aircraft out of controlled airspace. Therefore when an aircraft reports established on the LLZ we say "Maintain 4000ft - follow the localiser" and then "descend to altitude 3000ft, further descent with the ILS"
119.5 - with regard to opposite end departures against the flow of an inbound - I always let the inbound know to maintain 4000' with the reason "opposite direction departure climbing below you". Otherwise they will only ask toconfirm the landing runway....!
So easy to screw up when using both ends in a busy enviroment.