2 IFR Arrival chart questions
 

listening to ATC clearances going into Adelaide last week. I only have DAP charts these days and I cant find the answer to 2 questions that came up ?
1. why does the clearance given on frequency often say " maintain published speeds " ? Surely on accepting the clearance you would respect the charted speed restrictions unless told otherwise ?
2. the other ones a bit silly but ( Non-Jet ) STAR 's , are they for slower Turbo -prop(jet) aircraft or simply any aircraft that does not have a jet engine ?

Thanks for any assistance.

Hi Fluke, this instruction is usually issued with a crossing time, which comes with a speed requirement (May be the published speeds, may be a slower speed as required by ATC). When on descent this could be an indication that the previous speed restriction is now removed and published speeds can be maintained.
Not silly at all, yes - For traffic management the stars separate the Jet (Turbofan) traffic from everyone else (Turboprop/Piston).