Brought up by [this question](https://worldbuilding.stackexchange.com/questions/149313/how-to-build-the-cube-prison-from-cabin-in-the-woods?noredirect=1#comment467985_149313), the Reality-Check and Hard-Science tags' descriptions aren't in implied agreement (at least, as I read them) on if they can be combined.

Reality-Check reads:

> 
> Asks if a given concept is realistic in a given context. Answers
>  should say yes or no, with supporting info. **Compare this with the**
> **science-based and hard-science tags. This tag should never be the only
>  tag on a question,** because this tag frames how a question should be
>  answered, not the topic.
> 
> 
> 

(Emphasis mine)

Verses the hard-science:

> 
> Requires answers backed up by equations, empirical evidence,
>  scientific papers, other citations, etc. C**ontrast with:
>  science-based and reality-check tags.** This tag should never be the
>  only tag on a question because this tag frames how a question should
>  be answered, not the topic. Review the tag info before using this tag,
>  and flag your question for moderator attention once posted to have the
>  hard-science notice added.
> 
> 
> 

(emphasis mine, again)

So this question has two points of discussion:

1. Are these two tags mutually exclusive
2. Do the wording in these tags need to better clarify this? If so, how?