I've got three FM stations within nine miles of me that are each putting out 100KW of power. It doesn't matter what probing technique you use. If you're looking for low level signals, you have to use the 20 MHz filter. Otherwise, every circuit you work on has 100 MHz noise! I also make a point of using double-shielded coax for everything - preferably foil and braid rather than two braids.
If you want to find out what your local situation is, go to fmfool.com and put in your postal code. They say zip code, but it works for us, too. If you want to check the local situation for tv stations, go to tvfool.com.
Ed