Using this phrase suggests someone's actions may cause a chaotic or aggressive response. Raising the rent without notice will hit a hornets' nest among tenants.
Pro Tip 2/3
Metaphorical Use
It's mostly used metaphorically to describe a situation, not actual insects. Questioning the company's hierarchy is like poking a hornets' nest.
Pro Tip 3/3
Negative Connotation
The phrase carries a negative connotation of turmoil and should be used cautiously. Her controversial article became a hornets' nest of online debates.