MTT swaps etiquette

The other day I was playing a multi table tournament. It was 5 handed and paid the top 3. The situation was 4 of us had 7000 or so, and a bigger stack had nearer 20K or so. Clearly the bigger stack could kick us round and though first would be nice, 2nd and 3rd are worth far more than 4th and 5th. Prizes were something like 3K, 1.8K and 1.2K.

Another shortie offered me a percentage swap, and I said no, as it wasn't right. He said he wouldn't change his play, but I don't see how you can't. You immmediately don't need to fear the bubble at all, and can concentrate on first again. And with antes in, he can push your BB probably realising you would subcontiously tighten your calling range. Say blinds get to 1000/2000 and a 200 ante. He pushes with , 6 or 7K or so, and you wake up in the BB with the mighty 67 off. Having 50% in him would make the fold far easier to find?

He pointed out that a lot of swaps are done late on in MTTs, and I said that was probably true, but I am not sure that makes it right.

So is it Ok to take a swap here? OK if it is only small? Say 10% 20% or so. Or never OK?

I happily took a swap at the start of a 30 runner MTT not long ago. Even though I ended up on the same starting table, that didn't seem that bad at all, as I didn't know the draw at the time.

So if you answered no to the FT swap, how many tables would you need in an MTT before the swap becomes unethical?