I do not suggest for one minute that your certs are being given to students who are not capable.Nevertheless to give such advice to others to set up their own group without some quality checks is fraught with danger. There is a danger that any Tom ,Dick or Harry could set up their own group, call themselves Tenth dan, teach rubbish and charge a fortune to unsuspecting people.Therein lies the danger. If absolutely anybody can do what you suggest imo this is a recipe for disaster.
Before long you would have what I call John Wayne aikido instructors.A bunch of cowboys,
Self promoted guys with vastly inflated ranks, titles.Heaven forbid.Cheers, Joe.
Yes, as Peter and a few others point out this is already being done all the time. However, assuming that the person asking the question is qualified and is simply trying to navigate the bureaucracy of two organizations, one, the Y that is organized, and two, an aikido bureaucracy that does not have a process or method for producing certificates, where is the rub? You do what you need to do to make that happen.
The US tends to operate on Caveat Emptor with the exception of things such as Doctors and Lawyers where the stakes of screwing up are important. For the rest of the free market, it is "buyer beware".
What I like about the internet is we have access to information that 30 years ago we didn't have so folks can make more informed decisions if they so choose to.
Also, lets get real...do we really pretend that the Y cares or can even discern "quality instruction" or are they concerned with liability and making sure that simply nobody gets hurt?
In most gyms such as the Y they will have guidelines about what you can and cannot do in a martial arts class. Many clubs and gyms will limit striking, full contact, and kicking. Many will require use of protective equipment..outside of that stuff, they don't care if you are teaching "quality".