In one of my businesses, hotel booking, i also sell gift cards and market them agressively in festive seasons.1 year validity. 45% goes unclaimed, its now 20% of total profit (all legal here, expiry date in a large font)
That's not the same as putting $100 on a hotel gift card which you can use anywhere anytime at the hotels many properties, maybe to cover a pet fee or cleaning fee or parking, or to reduce the cost of a room during a peak cost period like 4th of july.
There's almost always a consequence for not providing value, and if 45% is unclaimed, that's not valuable to anyone but you.
I'd also wonder why so little goes claimed. I'd be worried about my product or service if people didn't want it, even if it was gifted to them.