the MakerDAO system has two parts, the DAI token and the MKR token. The MKR token is the governance token the is used to vote on things like interest rates debt ceilings, and other decisions. As people take loans out by over supplying ETH and getting DAI, the interest paid on these loans is used to burn MKR, this provides the incentive to keep DAI stable so that MKR keeps getting burned. If the system collapses then MKR is printed to make up the difference and restore DAI to a dollar. This would be bad for the governance tokens since their stake of MKR would get diluted and the price would go down.
In order for that to happen, it has to be trading on multiple exchanges and for it to fail, all the exchanges’ stop-loss orders must fail at once.
Nothing can be pegged with absolute certainty, though, unless you liquidate everyone’s position before the peg breaks. Look at how Soros broke the Bank of England.