I'm making a 3-tier cake for this Saturday. I will transport the cake unstacked to their house, then stack it there, and they will eat it that night. I'll support it with dowel rods. My question is, since I'm transporting it unstacked, do I really need the dowel rod down the middle? This is only my second 3-tiered cake, the first being for my family that we ate about 5 seconds after it was made!

No. No center dowel needed unless you are delivering assembled.

I would. Any bump of the table and there it goes on the floor. I couldn't imagine not putting one.

I think it's a personal preference as I've delivered stacked cakes without center dowel for thousands of miles covering several decades.

Some folks would not dream of delivering stacked some folks always deliver stacked because they don't want to be watched while they stack it up on site.

None of the bakeries I worked for ever used center dowels -- some delivered stacked some didn't.

So to me it's what you're comfy with and what applies to your specific needs at the time. For example I use the center dowel that's built into the base to thread cakes onto for my topsy turvy type cakes. But those I would deliver unstacked. A whimsical type cake I'd probably deliver stacked 'cause they're so messy.

Just whatever works best.

I never use a center dowel at all. When I deliver three-tiered stacked cakes I refrigerate them so that they're cold when they're transported, and they're fine.

I would not use a center dowel if you're assembling it on site. As long as your cake is assembled level, you don't need it for structural integrity.