It's like when caution was suggested re following "H' in his football picks last year when he was on an unbelievably hot run. Certainly no one can keep that up indefinitely while often betting into odds that suggest they have a coin flip chance of winning.
Some people might be inclined to increase their bet sizes then, but i'm more of the decrease or lay off practice. Others may even prefer to fade. Still others would continue to bet the same amount.
The thing is, though, if one lays off before the hot run is over, then they miss some winners. So how does one decide when the time has come to lay off or decrease bet sizes of a solid long term winning capper on a very hot run of mostly winning picks. That's impossible to know. It's a matter of guesswork & intuition.
It could be argued that if the guy is believed to be a long term winner that flat betting is the proper course of action no matter how hot or cold the guy is. OTOH, lowering bet amounts by a percentage (0-100%) when a good capper is very hot is a cautious approach designed to not lose what has already been won during the hot streak.