At least some of the responsibility for avoiding these situations lies with the person leading the trip - whoever booked the permit, or who has volunteered to rig, or is the person to whom Mr"I can do srt" is speaking. They have to go beyond accepting "I can do srt" at face value, and ask about some details, trips they have done, and explain the features of this cave which might be harder than expected.
Generally in the clubs (small in size) I've been caving with, most intake is generally a novice (ie no expected skills at all) and the club knows the skills of everyone in the party, the trip leader has probably also been helping to train said novice beforehand, and no nasty surprises await. It is harder in a larger club where not everyone is known, or where a "skilled" person joins that club. But the responsibility still lies on whoever is leading the trip.
No need for certification, or standardisation. But there is a need for communication, and people to take responsibility - not just for themeselves although that is certainly alos a requirement, but for others. Caving is a team activity.