When OnePlus 5 was unveiled, the owners of older OnePlus models received notification about the launch.
Now that the smartphone has been launched, the company has again begun rolling out notifications. However, it is asking the users to join a survey that will give them a chance to win a free OnePlus 5. While some people may like being informed about such events since they could get a hot prize, this is not the case with everyone. Some are quite annoyed with what they are calling as "spam notifications".
As for OnePlus, this could just be a marketing strategy from the company in an order to entice customers. According to the claims made by some users on Reddit, they have received such notifications a number of times over the last two weeks.
The main problem is that there is no way to stop the notifications for those running the latest stable version of OxygenOS. The OnePlus Push app can be removed altogether, but it is not as easy.
Those who are enrolled in the OxygenOS beta program and are running the latest software version can block notifications from the Push app by going to "Settings" > "Notifications" > tapping the three-dot menu in the upper right corner > selecting "Show system apps" > "Push" > "Block all notifications."
You should keep in mind that doing this will stop all the notifications from the app.
Commenting on this issue, OnePlus has stated "Feedback from our community has always been at the heart of product decision making and as part of this feedback loop, OnePlus 5 users have been sent a notification to share their personal experiences about the OnePlus 5 with an option to opt-out. This is to help with the continuous improvement of our products and to better understand our community of users."