Though inspired by this question, this tends to come up more often in relation to CLC Workbench. On occasion, people using commercial closed-source packages will post questions about using said tools or analysing their results. 99% of the time these products already have official support channels that the posters will have already payed for but either aren't using or have just hoped that we will respond faster (therefore performing the role of the company for free).
I personally am very much against answering such questions, since it has the perverse incentive of promoting companies not providing support for their products. Over on biostars we generally post something of the form, "This is a commercial product, you're already paying for support, ask the company". I would be in favor of a similar strategy here. Thoughts?
Note: The question that inspired this is not a great example, since the product in question is a wrapper around standard open-source packages. Nonetheless the site will inevitably face other examples in the future.