WiFi is 2.4 GHz and low power.
I could not stop my mind spinning on this so I had to comment, maybe more knowledgeable people could bring more light over here.
20dBm is 2.2V/50ohm and even if a small fraction (say 1% it would still be 0.22V) of that make it into the AFE (directly or via the test circuit) it could show up on the screen especially on lower V/div scale.
WiFi max power can be thought as small but
electrical proximity to sensitive circuits inside the scope make it not suitable for this purpose.
Did I got this right ? (I mean AFE is shielded and input is filtered but then 2.4GHz can sneak in more easily than higher wavelengths.)
There is a reason 2.4 GHz is unlicensed.
Wasn't that reason high atmospheric absorption/propagation loss that made ISM bands commercially unattractive and thus regulatory effort was not justified?