Earlier quoted context omitted.
If you prefer not to have solutions, pretend you don't have solutions. Having solutions is strictly better (for the reader. I'm ignoring the cost of producing them to begin with)
"pretend you don't have solutions" is not a realistic approach. The strength of people's conviction to this will probably fall on a bell curve and few can resist the temptation when the problems get really tough. Accounting for how humans are, I do not see how one can easily say "Having solutions is strictly better". I can easily think of cases where it is indeed better to have solutions but to say "strictly" require…
Without solutions at the back of the book, self-directed learners can't verify their own work. Don't cut out the less privileged learners from bettering themselves just because you have no concept of discipline.