Something as simple as a large cardboard box can hold in enough of the fermentation heat and stabilize the temperature.
By the way, there is a Belgian-Style Dark Strong Ale recognized under the BA guidelines.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk