How do you make a safe haven for incompetence? Make a rule, develop a process, or publish a guideline. I'm not saying that you should never propose processes or guidelines, but you should be very careful in why and how you do it. Organizations have a tendency to throw a rule or process at every mistake or problem that comes their way. This is absolutely the best way to protect you from incompetence either in management or your employees.
This also has the benefit of setting your organization on the path to widespread incompetence. Why think? Have someone design processes such that there is no need for intelligence, competence or creativity. Sad to say, but almost every organization I've worked with beyond a certain size succumbs to this attractive proposition, more or less. It has always amazed me to see business workflow charts where 90% of a project is about process management. The processes are designed around organizing and managing and communicating and 10% (or less) of a project is associated with actually doing the work of the project. One example I heard about was an effort to change a hard drive on a server. As I understand it, over a 100 person-hours have gone into planning the hard drive swap. A good sysadmin would have performed this task perfectly fine just by talking to the application customers and finding out when the server could be brought down to make the swap.
It is absolutely imperative to share best practice and document best practice guidelines - but this can be done without dumbing down the organization. Share best practices, share protocols. Don't develop a set of forms that have to be filled out in triplicate where every box has to be checked off regardless of its applicability to the problem/work/project in question. My workgroup has a set of protocols/guidelines for performing various tasks on a wiki. It is on the wiki in case someone comes up with a better way to do a task. They can then change the guideline for all of us to use.
It is absolutely delightful coming from a large corporate perspective to hear from vendors that are growing to the point where they hire a CFO. The first thing a CFO does is start instituting processes and rules. Everything must be completely defined such that the CFO's needs are met. Everyone must make their travel plans through a travel agency and do it 60 days ahead of their departure date. One can only submit expenses once a month and EVERY item must be associated with a receipt. One can only use the following approved vendors for X, Y or Z with no exceptions. If these seem familiar, it is only because one of the classes in corporate management teaches the principle that everyone is incompetent and everyone must be told exactly what they must do. The fact that one is also told to work very hard to only hire the 'bestest and smartest hhhooommmannns' is probably a mistake as it would be silly to hire people who can reason and think when that is clearly not what you really want in your organization.
I have also worked in the military defense industry as an engineer. I was always amazed at all of the paperwork and process to prove that we were doing the work as requested by the Air Force. In the early days of the defense industry, it barely took a handshake to set up a contract. These easy agreements of course led to the potential for corruption and graft. The most amazing thing is that the reaction to corruption and graft on the part of the military was not a scorched earth policy against the corrupted as one might expect. Instead, the military developed extensively detailed contracts, processes and guidelines to ensure that graft and corruption did not continue yet continued working with the very same people and companies that defrauded them initially. Instead of relying upon the common sense and reasoning ability of the personnel in the military requesting work to be done by the civilian companies, processes (the lifeblood of any bureaucracy) were developed and deployed with as much vigor as the D-Day assault.
If someone in your company makes a mistake, build a process so they are not able to do it again. If they make another mistake, it is clearly your fault in not providing enough process management and checklists to make sure they cannot make mistakes. When you get to the point that 90% of your staff are required just to manage all of the processes, consider yourself successful as there is almost no possibility of making a mistake in your work as your company's expected lifetime can be measured in days.