They also probably don’t pour very strong when they can get away with it, i.e., drinks with mixes, juices, waters. etc. Regular martinis are good because it is harder to cheat on the alcohol content.
I have heard that complaint about different ships. It can vary.
Some ships won't pour doubles and some will.
For example you can order a pina colada wih a rum floater and get it , and some ships don't want to pour it, since it is a double.
Having good relationship with the bartender is very important. - Tom