I came across the phrase「置いて行かないで下さい」. I am unsure as to whether this means "please do not leave it there", or "please put it down and don't leave". I'm thinking it's the first one, and that if it was the second it would be written as「置いて、行かないで下さい」, or maybe something else? Or am I way off with both?
「カネオクレタノム」 <--- 電報で有名な笑い話
I think you're right on-point on everything you said.
This enrty (below) used to be huge, until the WP-police ("the downvoters") censored it.
1. 「今日は、雨が降る天気じゃない」 と 2. 「今日は雨が降る、天気じゃない」
( I think both utterances are possible in casual speech. )
Today is [ not the kind of weather in which it rains ]
It's (going to be) raining today ; it's not good weather
■ ぱんつくった ( パン作った / パンツ食った ) ■ ねえちゃんとふろはいった? ( ねえ、ちゃんと風呂入った? / 姉ちゃんと風呂入った? )
行く after the te-from of a verb will almost certainly be parsed as a subsidiary verb, so 置いていかないでください means "Please don't leave it/me/him/etc here". And even if you put a (Japanese) comma after 置いて, people would still parse it in the same way. That comma is nothing more than a small pause between words. For example it may just mean the speaker said the sentence slowly and clearly.
To absolutely break the link between 置いて and 行く in written language, you need a (Japanese) period.
Put it down. Please don't go.