The point of the UBI is that we are already giving things away for free, and we're doing it inefficiently and creating bad incentives in the process. Right now

The point of the UBI is that we are already giving things away for free, and we're doing it inefficiently and creating bad incentives in the process. Right now it's entirely possible for a low-income worker to get a raise and end up worse off, because they cross the threshold for a means-tested program and lose more in benefits than the amount of the rais. The question shouldn't be "would a UBI discourage work", it should be "would a UBI discourage work more than the current system does", and there are strong arguments that it would not.