I have been blessed, as except for the beginning when I got 9 PMs about it, I am getting an average of 2 or 3 per day and as I am progressing it goes down even more ( but I expect as more people get stronger and decide to attack me more often I will have the issue )
but lot of people have said they get over 20 PMs about the glue vouchers and it feels like spam
I do not see the sense of that much SPECIALLY when there is room at the storage
a way to cut those messages would be for the glue one earns for the defense fights is that it goes automatically to storage if there is room, and only go to PM vouchers when there is no room at storage