We also feel the same way about the "One Click Masternode Setup" or "Masternode Setup Services" based solely on the fact that while they may not be directly able to access your collateral, they can turn your node off and affect your earning capabilities at any point. This in essence, could easily be used to cheat their users as well as manipulating the masternode reward system should they have enough people using their service.
That's fair. Although I would (unfortunately) think many users might feel less concerned about these 'one-click' services, where they can't access your collateral, since the risk isn't there in the same way for services where coins actually need to be sent. Also, many people just sit on their coins anyway, so having them be essentially 'staking' through a shared masternode might sound like a good idea to many, particularly if the returns are higher than actual staking.
The issue of 'manipulating the masternode reward system' becomes less of a concern as soon as you take away much of the individual user's risk (because their collateral is 'safe') and add more money to the equation. Perhaps if users understood the ramifications of shared one-click masternodes on the entire bulwark system they may be less inclined to go down this path.