When the Buccaneers fully guaranteed Adrian Clayborn's contract, they were the first team to finalize a contract with a first-round draft pick. In guaranteeing that contract, they set the market for first-round picks - and other teams aren't too happy with that. I'll quote Andrew Brandt on the matter:
Clayborn’s contract has become a polarizing issue in this year’s condensed negotiations. There are a few front offices around the league cursing the Buccaneers under their breath for creating a precedent that will certainly be in place now for probably the ten-year length of the deal.
Meanwhile, draft picks #16 through #19 haven't signed yet, while the players drafted immediately after Clayborn all agreed to contracts with only three out of four years guaranteed. Clayborn represents the breaking point in the first round, and the Bucs shelled out to get him into camp early.
Personally, I don't care how much guaranteed money Clayborn got. The Bucs can easily afford it, and that $2 million per year is not going to put a dent in any team's payroll. I'm just glad the Bucs managed to get Clayborn into camp, because they're going to rely heavily on him this year.