Sun bleaching is unlikely to have a noticeable effect in only a few days, unless it is getting the full force of the summer sun over the whole day. Though a couple of hours a day, over a few weeks will start to show visible effects of bleaching. As for your pouch, you don't state how long it has been exposed to sunlight, but I would guess that this hasn't happened over just a few days.
Barrels in a whisky cellar aren't likely to be effected by electric lamplight for 2 similair reasons - - The lights are only ever switched on for short periods, and low wattage bulbs are usually used - Thrifty people are Scotch Whisky Distillers!
Also, very little UV light is given off by electric bulbs, and the whisky is somewhat protected by a nice bit of oak. I don't think anyone has ever conducted experiments to see if whisky would be affected in the barrel by constant exposure to bright electric lighting, but over 30 years there may be a barely noticeable effect, though if the heat given off by the lights wasn't dissipated the difference would be quite marked.
If anyone has got a couple of barrels of newly laid down identical malt whisky, I'd be happy to pay the electric bill for 25 years to see if there is an effect, I'd also be quite happy to invite people to the bottling party too!