Keep in mind that in general reputation algorithms have ways to mitigate abuse such as someone just marking themselves on another account. But nothing is full proof and human judgement by viewing the data on the marking ledger is always the best option.
Should people who give out a lot of marks to people be considering something like 'marking whales'?
Keep in mind that in general I do not give a damn on these reputation numbers, and you do not either. We both use that "human judgement" as only safe way.
And 'marking whales', seriously? What devilish kind of 'marking whale game' is up to plot? Do I have to believe the guys with the impressive big numbers, anything they say? Nope, woun't happen. Couldn't care less.