If you have a product or service based online business ,accept fixed bitcoin prices with a refund.
For example,a customer buys your service or product for 50 USD worth of btc.The bitcoin price doubles after one week and he actually paid you $100.This would be really frustrating to him so you offer him to refund 50 USD.You kinda lose money,but you get a loyal customer,who is paying with btc.
Interesting proposal. That would basically be "the other way around" to what I proposed
here - in my proposal the merchant doesn't increase the price in the case Bitcoin goes down. The interesting thing is that in your proposal the merchant would not lose money measured in USD, only measured in Bitcoin - this could make it even more attractive. And above all: it would increase usage of BTC in bull markets, when people are eager to HODL.
The merchant could even charge a little plus for this "refund service" - e.g. 1% more - and then profit from hodlers even if the price finally doesn't go up.
Anyway,the bear market won't stop just because a bunch of people started accepting bitcoin payments.
That's true, but they can start a trend, and if it increases Bitcoin's circulation then this has a stabilizing effect. And if they use also the "backing" system I propose, with abundance of goods, then investing in Bitcoin becomes less risky even in bear markets, because people can spend the BTC a few hours after a crash and buy goods "to the price before the crash".