But on the positive side of the coin, the brick ones never got tipped over on Halloween...
Of course, to understand this you would have needed to grow up where there were a minimum of these two requirements:
1) Outhouses
and
2) Mischievous halloweenprankster kids (often described by the, um, victims as vandals or hoodlums) to tip them over on Halloween.
or
3. Worked on a British Building site.
4. A music festival
The chemical thunderbox. A wonder of the age.