A319
Flight Crew Air Transport Pilot (ATP)
ATC Issue All Types; Conflict Airborne Conflict
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented
Human Factors; Procedure
We were cleared to take-off; runway 1R; with the instruction to keep the preceding Airbus in sight.  I delayed pushing the power up until I saw the A320 rotate.  As I rotated off the runway; I was surprised to see a Business Jet (I believe it was a Hawker; but not positive) rotating off the parallel runway about 100 yards ahead of us.  Had we been advised and had a visual on the traffic departing the parallel; this would have been a little close; but with nothing said; it was quite the surprise.  If I had not delayed the start of the takeoff roll to get proper separation; we would have been much closer. It would be nice if the Tower would do their job of providing proper separation between IFR traffic instead of passing the responsibility onto the flight crews.  At a minimum; it would be nice if they were professional enough to advise us of the potential conflicting traffic if they expect us to maintain separation for them.
A319 Captain reports being cleared for takeoff on 1R at LAS; with the additional requirement to keep the preceding A320 in sight. The takeoff is delayed until the A320 rotates and results in a formation takeoff with a Hawker on 1L. The reporter believes the Tower is not providing proper separation.