Airline stubs or e ticket etc maybe helpful I guess if the stamp was unclear what flight you on. May save them some checking
When in late 2005 the checklist they left in with our visa the things they actually ticked was a very small percentage of what we had sent in.
Marriage docs, id, photos together, proof of residence, proof of income or abilty to support. If my rubbish memory is working
From what I haver read and recently seen on uk border force (although a difference area of the Visa business) Its almost easier on the CEO to say yes than have to make sure they dont have to decline as more work and paperwork. So make life easy for them