In which context the sonkeigo is used with the imperative form?

Question

I've encountered this example sentence for the word ポテトチップス (so there is no further context) where it is the case:

もっとポテトチップスをご自由に召し上がれ。
Help yourself to more potato chips.

And then I find another, but there is still no context because it's also an example sentence:

もう１杯召し上がれ。
Have another cup.

Answer 1

What you are showing is an example of language 'beautification' (美化語｛びかご｝）. Taking a word that is normally reserved for honorific language and applying it to a peer or even someone of lower status.

If you have ever said to a friend (in a contrived accent): 'Would you care to dine with us tonight?' instead of 'Wanna have dinner with us?' you have used it already.

Some might describe it as 'effected', but it is just the borrowing of a word or expression normally reserved for honorific speech and applying it to daily use.

A mother will often say tell her child to 「召し上がれ」.

What will signify that this is not, in fact, 尊敬語 is the fact that you wouldn't use the harsh 「れ」ending when addressing one's superiors.

Also telling would be the fact that there is no honorific prefix (お or ご) applied. Assume that if there is none, it likely is not 尊敬語.

As 尊敬語 forms are used quite frequently in regular conversation for effect, it can sometimes be hard to decipher whether it is being used in its original intent or to simply make language more florid without reading from the surrounding context.

I would recommend referring to other posts surrounding the use of 美化語. Many are listed here.