or melt your ice cream if you live further than 10 minutes from the store and you weren't in the grocery store for 2 hours to let the exhaust cool down.
I drove my box across country with the factory muffler on it and dangit, the rear trunk got so hot it melted the laces of my tennis shoes partially into the sole!
Really.
So the answer is emphatically YES. It gets hot back there.
Of course, adding just about any aftermarket muffler solves the problem due to sheer size and placement changes.