Most of the nets have small radar reflectors at each end and some in the middle. The same with the hundreds of nets I've seen off the US west coast.
What can I say about deadheads and floaters? A 30' long, 4' diameter log floating 6" above the surface makes a great radar return. Or - maybe I've been lucky all these years and mysteriously imagined those radar returns, and just luckily deviated to avoid all those imaginary returns. Two weeks ago I made an 80 mile round trip in waters that were full of floating logs and crap - it all showed up very nicely on my poor old radar.
I have had surprise close calls with wooden boats - an oncoming 50' woodie came out of 5 yard fog in Rich Passage - narrow with 6 knot currents. Both he and I were hugging the shoreline to avoid the 10 knot ferries that come thru twice an hour. We were both doing less than 2 knots so were able to avoid each other.
I suppose the new radar will pickup all wood boats and non-reflective surfaces?
My point was that I have been very pleased with the performance of my traditional radar in over 1500 hours operation in stressful conditions. I am hard pressed to understand what HD or Digital radar can do for a small boat moving at 3 knots that my traditional radar does not already do. If my boat is only moving at 5' per second and my current radar gives me 60 seconds warning that has always been plenty of time to avoid. What more can I expect?