since the arrival was a RV ILS, the departures were obviously RV
That's rubbish and a dangerous assumption.
A1. Basic pre-flight planning. If there is a SID, or a STAR, expect it until you get told otherwise. Doesn't matter who provides what from where - if it's published, it could be used.
A2. Were you placed on a heading - or still on the SID? If the former then you should have checked in with your level climbing to and the heading assigned. If not - then you should have checked in with the SID designator and level climbing to. You effectively placed yourself on a heading without an instruction from ATC.
Sorry, but - sloppy planning, piloting and R/T from yourself that could have led to an incident.