“It also includes giving him first choice in many other situations. The fact that people don’t do it is — to use the popular parlance — no rayah.”
That is not true, the Magen Avraham noticed it was the minhag where he was and most other places the people were not giving kohanim kedimah in such situations. He says it is because kohanim today do not have yichus like they used to and therefor they are not entitled to such honors.
There is a great shiur on YU you can listen to about this. just type in yichus of kohanim today.
see also kohen.co.uk