Printing error on a Chinese lunch delivery bag

Eric Pelzl sent in this photograph of a bag from a lunch delivery that contains an interesting printing error:

The Chinese characters on the bag read:

zhēn'ài dìqiú bǎohù huánjìng 珍爱地球 保护环境 ("treasure the earth, protect the environment")

The Pinyin reads thus:

zhēn'ài dìqiú bǎohù jiāyuán 珍爱地球 保护家園 ("Treasure the earth, protect your home")

So we find a discrepancy in the last words (the last two syllables) of the Pinyin and the character versions.  Otherwise they are identical.

Incidentally, the word jiāyuán 家園 may be translated as "home", but it also connotes "home and its surroundings".

What's the most likely explanation for how this happened?

bǎohù huánjìng 保护环境 ("protect the environment") 1,500,000 ghits

bǎohù jiāyuán 保护家園 ("protect your home") 285,000 ghits

As a four-character expression, the first is over five times more frequent than the second.

zhēn'ài dìqiú bǎohù huánjìng 珍爱地球 保护环境 ("treasure the earth, protect the environment") 10,800 ghits

zhēn'ài dìqiú bǎohù jiāyuán 珍爱地球 保护家園 ("treasure the earth, protect your home") 4,810 ghits

As an eight-character, two-clause expression, the first is 2.25 times more frequent than the second.

There is, however, a completely homophonous, and very nearly synonymous, formulation:

zhēn'ài dìqiú bǎohù huánjìng 真愛地球 保护环境 ("love the earth, protect the environment") 6 ghits

zhēn'ài dìqiú bǎohù jiāyuán 真愛地球 保护家園 ("love the earth, protect your home") 803 ghits

The latter is over 133 times more frequent than the former.  Maybe that's what was in the mind of the person who was responsible for the Pinyin, and that may have been what triggered the error.