Explain the significance ?
Like I said on a previous page, the tunnel is owned by a private Swiss company, it's super tiny, it's one way, and you would have to spontaneously block it for hours. It would be a way bigger danger to cycle through with a peleton than any snow or rain on any pass. If someone crashes you don't have exit options or ways to reach them quickly. I also don't think the Engadin Kraftwerke give a *** about the Giro to even consider changing their business as usual for such a charade.
But either way, apparently cycling anywhere before Prads is out of question anyway, so they don't do the start in Livigno nor cycle through that tunnel (which I guess was never an option)
Before I thought they'll send the non race relevant cars (media, some support stuff) through that tunnel and try to get over Umbrail by busses as quickly as possible (might take ages). Now I think they might be tempted to send the riders through the tunnel by cars with just the support cars behind because Umbrailpass with everyone still takes ages.
I guess that's also where the confusion and hold up is coming from right now, teams don't know wether to go through the tunnel just by cars or get everyone on the busses over Umbrail.