Midair Warning

That's still true. But I have always found ATC to be quite vigilant in reporting traffic with flight following or IFR in VMC, if not necessarily providing collision avoidance vectors. They do still get radar alerts if you have a TXP, and sometimes primary targets. One time flying 500' offshore Monterey bay at 500' in a citabria, what was then called Monterey Approach called to tell me that there was a primary target my altitude 1 mile, "but it could be an 18-wheeler on Highway 1."