こんなことしたら、前例になっちゃうよ。の英語

If we do this, it'll set a precedent.

That will create a precedent―establish a precedent.

It will create a bad precedent.

It will create a bad precedent―establish a pernicious precedent.

There'll be hell to pay if you do that.

You'll have to pay dearly for it.

There'll be the devil to pay.

You do that and I'll fire you.

Such a step may be attended with serious consequences.

If I had you do this for me, wouldn't I then receive an essential understanding of the fundamentals?

Once things start going this way, in the end they'll all be much of a muchness.

Doing that sort of thing makes you look stupid.

If you do that, it will only bring about a contrary effect.

It would be counter-productive to do such a thing.

If you do that, our friendship will be over.

That will complicate matters.

Such conduct will cost you your place

It is as much as your place is worth to do such a thing.

That would be rude [impolite].

It will cost me my place to do such a thing

I shall lose my place if I do such a thing

It is as much as my place is worth to do such a thing.

It will create a scandal―give rise to a scandal.

That would make it impossible for me to make a living.

That will complicate the matter.

That is as much as my job is worth.

If such a thing should happen, what shall we do?

That complicates matters.

I will pay you in your own coin.

If I were to do such a thing, I should be a public laughing-stock.