Why? Those problems should be able to be mitigated. Wouldn't it depend on how the fins are mounted? I understand there is a large leverage difference, but you get that with filleted fins too.When designing a removable fin system, keep in mind the leverage of the fin vs the mounting. If the fins are 14" semi-span, and the mounting is 1" for instance, there are going to be problems.
Gerald
I'm thinking having both sides of the fin tabs held in place in the way @Alan Whitmore described would supply about the same support as a threw the wall fins with fillets as long as the side supports are strong and well mounted.