panettone - lievito madre - to wrap or not

It's panettone time! So I have to built my lievito madre (50% hydratation)

When I maintain liquid levain I feed it and then I put in a plastic box or a jar and let it grow. 

But, with lievito madre, I've been told to wrap it in a cloth so it won't expand much. Is it really necessary? Will I get a different result or it is just tradition?

Thank you