Quote directly from the ETF site about the tube in question:

"Though there is some minor damage to the phosphor due to the way in which the tube was stored, the large spots in the picture are because the safety glass was not cleaned before the tube was installed."

It would help to know exactly what 'damage' means, but looking at the picture and seeing it in person I'd have to say there's little to no risk of anything catastrophic happening to a tube down to air.

http://earlytelevision.org/images/45...82_375x250.jpg

I know Bob only puts packing tape on the necks of his 15G's, but only to keep debris out. There was some talk about purging them with nitrogen for long term storage, but it all but stopped after seeing the RACS rebuild come to life.

There was a rebuilder in Vancouver (Burnaby) BC that had a bad run of tubes when they left them down to air over a weekend.

I remember some 10" PIL tubes for a portable TV-VCR that never did produce a good picture on those left over a weekend. The ones that were done over the week were OK.