The JWs I've spoken to say they can be neither disciplined or disfellowshiped for reading the religious views of others. Years ago, my grandparents kept a publication of daily sermonettes or devotionals put out by, I think, the Methodists. It wasn't heavy on doctrine at all -- it was just "feel good" stories with morals. Each day my grandfather would read one at breakfast. When his JW family members were there they didn't make a huge secret of not approving of it and would not hesitate to criticize areas in which they disagreed. But what irked them most of all was any reference at all of going to Heaven, a hope of which my grandfather held very strenuously. So even a small reference could turn into a protracted discussion.
My grandmother, a sweet old soul with a great deal of faith, but not even a smidgen of doctrinal knowledge, wasn't comfortable with the idea of just dying and becoming nothing. It became such an issue with these devotionals that my grandparents had to suspend them during these family visits.