ISSUE: I have been watching SELL XMR for fiat (SEPA) tab of the RetoSwap (Haveno fork) for a couple of weeks and there is rarely an offer below 3% fee. Most offers are around predatory 6% fee.
Since there is low amount of offers, some people put the 9% or similar dirty fee and this seems to be pushing up the average % rate of the future offers, making the Haveno not a good option for trading. When trading reversible pair, you do not want to create your offer, because you can not select with whom to trade by placing a limit on your trading partner (like account age and such).
SUGGESTION: Maybe if the maximum allowed spread from a market price is set to 2.5% or similar, there would be less predators and more people who really want to do the fair/market price trade. As a newbie when you open the app and see the SELL/BUY spread for fiat like 12%, it is pretty bad place to trade.
The point is that the value would need to be default for everyone so makers needs to lower their fees. As has been said the fee/spread would have to be set the way so the users cover their cost (do not loose anything by trading) and also has some benefit out of the trade (like up to lets say 2% buffer).
I dont think forcing people gonna help. This is kind of censorship imho.