If Reiki is Universal Life energy then it includes all energies, it is not selectively 'good' only whatever that may mean. Your stance could be taken if one would also proposes a Universal Death energy.
IMO what you describe is the 'happy, go lucky' attitude which works fine until the proverbial s..t hits the fan.
It also assumes the notion that we are in conscious control of things. Psychology demonstrates that this is not the case at all. We are larger than what we appear to be, have many more aspects than we could ever imagine, and have less control over things than we think.
To step into this and try to influence it while saying 'nothing can go wrong' is foolish.