OnePlus isn't having as much success as they'd hope in the low-cost flagship segment. Increased competition and other issues is making the launch of their OnePlus 2 difficult. To boost sales, the company offered to sell the OP2 for anyone without an invite for one hour. They're also trying a new marketing tactic that might not be their best idea.
OnePlus has attempted contests in the past, such as Smash The Past and a controversial photo competition. Neither went well. Their new approach is good in theory, but customers aren't likely to enjoy it any more than past contests.
The company wants customers to donate their Galaxy S6 / S6 Edge / S6 Edge+ and Note 5 devices for a free OnePlus 2. All donated phones go to Hope Phones, an organization dedicated to providing medical technology to people in need.
With the Note 5 and S6 Edge+ being worth nearly double the OnePlus 2, it's unlikely many customers will take their deal. It might also have been better if they'd opened up the program to more flagship phones in 2015 than just Samsung.