C-Quam is very sensitive to co-channel interference. At 270 watts
they'd be vulnerable to every signal. The resulting platform motion
would make every listener run for their barf bags.

Just like most FM Stereo receivers, modern AM Stereo receivers employ
a Stereo Blend feature which progressively blends weak and/or unstable
signals toward mono in order to improve the reception quality.

In general, considerable improvement has been made in the quality of
AM Stereo reception of weaker signals. The following web site offers
some sample recordings of the new Fanfare FTA-100P tuner, receiving
clear, noise-free AM Stereo from stations up to 80 miles away during
the *daytime*:

http://www.fanfare.com/soundbites.html