Handy, yes...
...but there is always someone around willing to "game the system" by claiming child abuse or any one of a myriad of "actionable issues" that (in a just and perfect system) may not prevail in the long run, but will (in the short run) cause no end of hurt for the organization that innocently provided the service. It's not the honorable way of making a living, but the world is full of less than honorable people, and occasionally they bump up against the rest of us.
This threat (of having to provide the defense, not the actions of the childcare folks themselves) is why businesses and employers opt out of providing such arrangements. It's an inconvenience for most, but less of a chance to take for the group that would ultimately have to bear all of the costs of such a course of action.
In short, the actions of a very, very few end up spoiling things for the very, very many. And, let's not forget that while there have been some cases of people crying wolf where no such wolf exists, there are also many, many cases where there was a real problem in the first place, cf the Holy Roman Catholic and Apostolic Church's recent struggles.
To say that organizations should stand up to such bullying is an easy (and popular) course to take as well. But, that's just talk and empty assertions - once the gamer/bully starts in on the innocent provider, all of that talk never translates into action (like paying a portion of the legal bills of the defense). Instead, those who were so quick to call for standing up are suddenly nowhere to be found.