My tris are very fatigued after my chest, but then I go straight to close grips, dips, and skulls. Of course there is the significant drop in weight than if they were on their own day. But, the weight still goes up, and my tris get blasted.
Ive almost always worked tri's on chest day and never had any problems, sure weights are a bit lower than working fresh tri's, but honestly I have been making the best gains by blasting tri's after chest and using heavy movements.