Can the fees in a coinbase be used to launder Bitcoins? Generally Bitcoins coming from a coinbase are considered clean as they are newly generated. However while answering this question I realized that mining pools could offer to launder Bitcoins in the following (in its edge case even extrem) way:

Let's say I want to launder 1 Btc


I create a chain of btc transactions with a relatively high fee (1000 Satoshi per byte). In the extreme case  I could even make an extremely large transaction by including a couple of outputs with large scripts producing 1 tx which has basically the entire amount as a fee. 
I send this (those) tx only to the mining pool that helps me to launder the Bitcoin. 
The mining pool then sends me an output from the coinbase to a new Address of a value less then the 1 btc (taking their share of the laundering operation) also since I wanted to launder I could receive several smaller payouts to various addresses. 


Let's say this is impossible due to KYC requirements of miners. Such an endeavor could also be achieved by solomining such a block by renting out hash power. 

Of course such an extreme tx would already look suspecious but I could create a similar situation by spammimg tx during a high fee market (or even producing such a fee market by spamming.) 

Somehow this picture makes me worry as it seems to me that criminals would not only be incentivised to do so it would also interfere with the entire ecosystem. 

Am I missing some point here? Why has that not been done yet? In case of stolen coins (for example quadrica exchange, it seems to me that it would even be worthwhile to just create a mining operation for such an endeavor)
While nothing stops you from paying a high fee to a miner and claiming it out of band, trying to launder any significant amounts through this would likely be discovered and linked fairly quickly.

A pattern of disproportionately high fee transactions appearing in blocks that are mined by a subset of miners would be noticeable, as would linking the money - If you are laundering 10 BTC and put it through via these fees, I simply need to track the spends of the coinbase output instead of spends from the original 10 BTC utxo.

Of course, you could do this piecemeal by laundering smaller, less noticeable amounts like 0.01 BTC per tx, up to 0.2 BTC per block, but that doesn't really scale to a significant amount, especially not once you take out the miner's fee. Moreover, unless you are able to bring all miners on board, you could only do this a handful of times a day (assuming you manage to convince a single large pool), which again does not scale up to any significant amount of BTC, especially if you stick to doing small amounts.

It's likely simply not worth the effort for miners or launderers. Sending coins to a KYC free exchange, or exchanging them P2P for other coins, especially ZCash and Monero, likely has much higher throughput.