When I was playing on normal and hard, I banned all cheesy tactics.

After the third campaign that I lost in expert (the longest one was 75 years), I opened the cheesy tactic book once again. Not using all of them, but I use quite a few.
- Edge/corner camping when defend is the most common because I hate to see the AI try to flank my strongest side of the formation.

- Trading and dominating the sea comes in second because the Sicilian always ask for it.

- Third is baiting the AI when they try not to be stupid. It's fun when making a fool out of a fool.

- Reloading comes in fourth when the AI Crusade try to use my shipline when they are at war with me or when they moved North into my provinces while they should have moved South to the target.

- Make money from rebellions is the fifth because people are going to rebel sooner or later.

Not all good reasons, but I really use those tactics quite often.