Personally, I have used ccts. with and without a series resistor over quite a few years.
I wouldn't jump up and down saying a resistor is needed, but if it makes someone feel better to do it their way, all the power to them.
It's always nice to compare things.
Having a high and low quality scope looking at the same signal might be interesting.
OTH a series resistor is dirt cheap, oh what to do? 
.