Sorry, I wasn't clear: Obviously, a parent may have done something that makes supervised visits absolutely necessary! My only point was that, if SV is ordered, it should be arranged such that each visit is not in jeopardy of cancellation, because the non-custodial parent is scrambling to come up with the money to pay the supervisory service, or having to choose between paying support and paying to see the child. And that happens.
My case is not at all the same as Flor's, but yes, we've had some experience with SV. My husband (who now has sole custody of his child) has an ex who was determined to marginalize him, in their son's life. One of her many methods was to repeatedly seek any excuse to request SV. (To give you a taste, once she requested it based solely on my [now] husband and I starting to date. Our sons were already friends, so sometimes we did things together with the kids. Mom complained that my [now] step-son knew and had a good relationship with me before the dating, for his dad to "pursue" me was a "malicious attempt to sabotage their son's support network" and that, "Visitation is for parent and child to have contact with each other, not for them to engage in social gaiety together." !?!?)
Only once did the court actually order SV for my husband (temporarily, until Mom's latest "abuse" allegation was investigated and thrown out), but that allegation and the SV conveniently fell during a period when he was between jobs, had huge lawyer/court-ordered mediator/C-O psychologist bills from the custody battle, and was trying to keep up with hefty C/S payments that were based on his previous income. And then, suddenly, seeing his child cost $100/hour! And if he didn't have it, Mom's story line was that he "didn't care about visitation".
Thankfully, not every custodial parent in an SV scenario is like my husband's ex. But even when SV is needed, no one should be cavalier in saying, "Just hire someone to do it." Care must be taken so that supervision is workable. If "the powers that be" have determined it is still in the child's best interest to have a relationship with that parent, then the child should never be denied a visit just because that parent can't afford to pay the supervisor, that week. That's all I meant.