Math::RandomFloat01 is currently sampling from an uniform distribution in the range [0, 1]. The common use case of this method is for handling probabilities:
if (Math::RandomFloat01() < m_fMyProbability) // do something
Whether 1 should be included or excluded can be argued based on what happens when m_fMyProbability = 1. In that case the condition should always be true, which is technically only the case when 1 is excluded. Using <= is also not a solution, as we just shift the problem to m_fMyProbability = 0 instead.