I don't think you can just run 'sed' on any random iOS app, any random symbian app, any random smart-TV app, some other guy's service that hits your APIs and feeds, and so on... :)
Now, that could be a valid issue, indeed, though not sure for how long I care about those devices continuing to work without any valid upgrade path... Using things like HSTS and CSP's `upgrade-insecure-requests` would help here for clients that do support it.