I sure see your point, and tend to agree
it is just that there are so many on the market that are not like yours
and I often don't get to choose what hardware is bought before it is bought
also they tend to be the smaller lighter ones, so people get them for portable use,
and then they connect them wrong.
either way, it is an issue that seems like people should think about before they fry a radio if they got one of the "less than ideal" ones
here is a guy that shows the issue with a similar test
page 5 shows the over voltage of the PWM colar controller
http://www.schams-solar.de/download/DESCRIPTION/comparison-mppt-pwm.pdfnow he connected a power supply that is not as current limiting as a solar panel, and that is why he sees what he sees on the scope with the battery still connected
this one sold all over the place has the issue
http://www.amazon.com/Sunforce-7-Amp-Charge-Controller/dp/B0006JO0XI/have seen it at boating stores, RV stores, harbor freight, ham radio stores, frys electronics...
it has been for sale for many many years and lots of people buy it, and there are many others are designed almost like it
you can usually tell them because they have only solar and battery connections (no load connections)
they have 2 LED lights, a charging and a charged, and they have a cut in and a cut out voltage listed with no option for battery type
when you open them up, they have no inductors and no large heat sinks
also usually no chips at all, discreet components only
they are out there, so watch out for them.
edit:
one more thing,
quite a few solar charge controllers are also positive ground,
I have that seen confuse a few people that expect everything to be negative ground