If you're going underwater though, you should be concerned about sea pressure. At 44 pounds per square inch of pressure for every foot you dive, the lid is the only concern you should have. Once the outlet pressure exceeds the inlet pressure, your seal is gone, thus resulting in very salty beer.
Alas, it sounds like you're staying above water so you should be fine as pressure DECREASES at higher altitudes.
Primary - Bluebird Bitter, Negra Modelo
Secondary - Flanders Red
Drinking - Independence Pale Ale V1.0, Trappist Style Dubbel, Dunkelweizen, Saison, Fat Tire, SNPA
Conditioning - Chimay Red, Imperial American Pale Ale, Independence Pale Ale V2.0, Belgian Wit
Kegged - Bluebird Bitter