Mafia: general discussions.

No one forces you to apply percentage-based protection to a powerful game role, but very often there are situations when it is not entirely clear whether or not a particular character needs to be strengthened. In such cases, those same 25-50% would be just right.

+25% protection literally means that with a 25% probability, the character will be strengthened by a factor of two. And with a 75% probability, the character will not be strengthened at all. This is not the same as strengthening a character by 25%; it is very important to understand this, and this is one of the problems with probabilities: it seems that they only slightly change the situation, but in reality, it is a powerful element of randomness, completely unpredictable, but radically changing everything. So, I would never introduce any small "enhancements" in the form of 25-50% protection.
It's a different matter when we have a character who, according to the setting, is lucky and unpredictable. Then, perhaps, it makes sense to introduce probabilistic protection specifically for him as a unique feature. Of course, the Lizardman wouldn't like such an option, but it is relatively democratic: at least it is possible to take into account the presence of this feature in only one instance of such a role, and it is unlikely to seriously disrupt the balance; it is not the kind of absolute chaos when every second role has probabilistic protection.