In my city this tactic is being used to lock out gyms near parks that are off the main avenues. While the botters and spoofers have over taken nearly every gym on the avenues. 'Egg' squatting is common in certain areas too.
It's only on the north side of the city and in low density areas where 'honest' gym battling can occur. And it's still the worst return for your time unless one exploits or cheapens the gameplay interaction.
It's a really crummy situation.