For those that use bubble tea straws as support under each tier, do you also use any dowel or support that goes through all tiers?  Is this necessary?  Will the tiers slide if I don't use a center dowel?  Thanks for your help!

I personally don't unless the customer is transporting themselves, or it's something out of the ordinary. But I'm a really careful driver and have been doing this a long time, so I know how my cakes behave. 

So you only put the straws in the individual tiers, and stick the tiers together with buttercream so they don't move?
 

ASometimes I might put a little royal on, but usually not. My tiers aren't slipping around.

I always use a dowel. You can be a safe driver but the others on the road may not be. I also don't know what happens to the cake once I have delivered it. I may set it up on the cake table as requested but soneone may come along and decide it should all be moved. You never know so I always play it safe. If it's a heavy or tall cake I use hidden pillars, they have a wider diameter and are made of heavier material so stronger than bubble tea straws.

If you put a dowel through the center, do you use a sharpened wooden one?  I'm afraid if I do this, the whole cake will collapse!
 

I don't use dowels for anything. I use long skewers, like you would use for shishkebobs. And no, it doesn't collapse anything, just hammer away firmly and steadily, until it goes thru the very last board into your drum. How big is your cake?

That's a great idea! The cake is 3 tiers - 4", 6", and 8".  So before you put the skewer through, you don't put any holes in the cake boards beforehand, right?
 

Definitely not, I'd never get them lined up again. :D Unless you're using hard plastic plates, or masonite a sharp dowel will puncture thru everything nicely. And I definitely wouldn't jam a dowel thru a cake that small, I'd use a skewer. And if I were delivering it, I wouldn't use anything at all. 

So AZ, do you think a cake safe is a necessity?  I took some flack on another thread for suggesting that it's overkill if a person knows how to properly stack and drive with cake.
 

AI don't think it's necessarily over kill, I'm told it's a wonderful.product, and wouldn't want to knock it. I think there are plenty of us that just don't.find certain products necessary, is all. I know how to handle my cakes properly, from construction to delivery, and don't feel the need for a bunch of extra stuff. If something makes you feel better and.secure, by all means, do it, or use it.

AExcuse the random periods, fat thumbs. :-D

Thanks everyone for your replies!