Taking into account the answers in this question and the answers here, answers recommending anything (hardware, software, etc.) that isn't directly asked about in the question will be treated just the same as any other answer in terms of content and quality.
To use the original situation as an example, if an answer is posted recommending a software alternative to a question asking about hardware, the fact that it recommends software won't be grounds for deletion. The answer will only be deleted if it is found to fall into a flaggable category (e.g., not an answer, link only, very low quality, etc.). And it has been determined that these answers do answer the question asked, so the "not an answer" flag does not apply.
Disclaimer: this is a modified version of my answer here because the question is closely related.
I think this kind of answer falls into a grey area when it comes to determining how it should be treated. The problem is how the information pertains to the question asked.
An answer recommending software doesn't recommend something that is asked for and instead recommends a good alternative with its own pros and cons. On one hand, this can be seen as "not an answer" because it doesn't address the question. On the other hand, it is perfectly fine because it addresses the underlying problem the OP wants to solve.
This brings the situation to a fork in the road where we have to decide if we will accept any answer that solves the problem regardless of what the solution is (desired hardware, undesired hardware, software, etc.) or if we will only accept answers that recommend the item asked about in the question (which has to be hardware of course).
I'm thinking we should allow this kind of answer simply because it provides a solution to the problem, which is ultimately what people want out of a question.