From a SEO standpoint it makes sense to
not use frames at all. And if you use them provide a useful alternative, not such a useless text. For example, if a Flash object with interactive content is included and Flash isn’t supported, provide a simple HTML alternative that still allows for the site to be fully usable with more basic funcionality. Same would apply here, so rather than such a warning message, provide a link to the actual content and some text about what the user will find there. For one, this helps SEO wise as useful keywords are used on your page, and secondly that’s proper
graceful degradation.
Of course, if you wanna do it properly in the first place you would rather approach it from the other side, meaning
progressive enhancement.