Head smashing was also present enough in episode 5x09 to give us reason to believe Negan is around. When Noah found his old house, he found his mother with her head smashed in the living room. Very similar to what Negan did to Glenn.
A trade-off is a situation where you make a compromise between two things, or where you exchange all or part of one thing for another. ...the trade-off between inflation and unemployment. American English: trade-off
Trade refers to buying and selling of goods and services for money or money's worth. It involves transfer or exchange of goods and services for money or money's worth. The manufacturers or producer produces the goods, then moves on to the wholesaler, then to retailer and finally to the ultimate consumer.