Q:

What to do with the white plastic tube in Dahon city vybe c7a?

Just got a Dahon city vybe c7a:

It has a white plastic tube at the bottom, what should I do with it? It seems to prevent the seat pole from sliding down.

A:

The seat clamp prevents the seat from sliding down. Not a plastic tube of any kind.
My hunch is that it's meant to be taken away. It's there only for some packaging purpose.

A:

When you lower the seat all the way down for folding it up, the bottom of the seat tube will rest on the ground. 
When they shipped the bike, they included the protector so that the seat tube wouldn't puncture the bottom of the box. You can safely throw it away, or ....
if you have wood flooring, you'll note that you can damage the floor with the seat tube. You can protect both your flooring and the bottom of the seat tube from scuffs by using the plastic protector.
You can safely lose it with no loss of function. 

