Bringing clients to visit a factory itself is not the problem—the problem is whether, at the time of making this decision, your working relationship with them has enough 'stickiness' to withstand this risk.
When assessing, consider these points: First, how deep is your cooperation with this client? Is it just a simple buy-sell relationship, or have you provided integrated services, quality control, logistics coordination and other added value? If the relationship is built only on your knowing this factory, then your role ends after the introduction. Second, does the factory have a clear consensus? In Old Zhou's case, the factory received kickbacks and pass-through fees, and had motivation to bypass the middleman due to profit incentives. If there's no clear cooperation agreement beforehand, this risk persists. Third, is the value you provide to clients clearly visible? If clients don't feel your contribution, they naturally think 'having an extra middleman is unnecessary.'
In summary, the issue isn't whether to bring them or not, but whether your position in this relationship is solid before you do.