I've heard many times said as an argument in favor of broadcast regulations that the radio wave medium (the atmosphere/ground) will become "polluted" if people send radio signals at whatever frequency and power they want. The signals might also cause "interference".
First, what is meant by signal pollution and interference? Do they mean the same? I think "interference" of signals can not mean that signals are colliding because radio waves pass through each other. Does it mean that electronic equipment is affected?
Second, if radio wave interference or pollution is the reason behind radio broadcasting regulations, how is this interference or pollution a problem with radio wave receivers? A radio wave receiver is tuned to a specific wave frequency, so should it not just ignore signals of other frequencies that aren't meant for it?
Thanks for reading.