Certain scenarios make it pretty clear that freeriding isn't always wrong. Robert Nozick's example of the freeriding group radio refusenik is a nice example of permissible freeriding. Generally speaking, it just can't be that an aggressive neighborhood association can saddle me with endless obligations to contribute to their collective schemes. Likewise, an enthusiastic PTA may generate any number of projects that do have benefits for all, but we wouldn't want to say they have the power to make it obligatory for parents to pitch in on all of these things. The basic intuition here, I think, is that there's a difference between receiving benefits you requested and receiving benefits that come unbidden. But what about these unbidden benefits? There are cases and then there are cases.
Here are three that involve individual rather than collective benefits, but I think they're illuminating nevertheless:
Case #1 - The Accidental Subscription. Suppose due to a mistake somewhere, you wind up being sent a subscription to Rolling Stone. You receive it every week and read it, not bothering to contact the magazine to let them know their error. (Real life example!)
Case #2 - The Requested Subscription. In this scenario you get Rolling Stone because you requested it.
Case #3 - The Double Subscription. In the third case, you have a requested subscription, and then an accidental subscription starts to arrive. You think "Lucky me!" and cancel your paid subscription. You continue enjoying the accidental subscription without paying for it.
If benefits must be requested for you to have to pay for them, then you have to pay only in Case #2. My intuition, though, is that you have to pay in both Case #2 and Case #3. You didn't request the subscription you go on enjoying in Case #3, but your actions are tantamount to requesting it. Your actions show you'd be prepared to pay, if it came to that. After all, you're on standby, ready to do differently, if you're ever threatened with losing the benefit. You paid for a subscription before you got lucky, so presumably you'd pay again, if the free copies stopped arriving.
This analysis carries over pretty well to cases where one benefits from a collective project. I don't have to support the neighborhood radio show because, though I may enjoy it, I'm not on standby, ready to do differently if my non-participation threatens the show. I'm prepared for the show to fail. Some goes for many (but not all!) PTA projects. I'm not on standby, ready to do any differently. Vaccination is different. Many refuseniks would presumably participate, if their non-participation threatened the immunity of their child's school. The vaccination refusenik is therefore not just a benefitter from but a welcomer of immunization. In fact, more than that: the refusenik is poised to participate more, if others participated less.
Now, collective projects are more puzzling. The magazine subscriber in Case #3 is prepared to pay, if paying is needed to keep the magazine coming. He's on actual standby, ready to take out his wallet. The vaccination refusenik is not on actual standby, but only on "hypothetical" standby: she would be prepared to vaccinate, if (contrary to fact) that were ever needed to preserve herd immunity. Arguably, though, the same moral flaw is on display in both cases: putting yourself on mere standby, while others actually pay for a benefit you value, makes you an exploiter of actual payers.
If you're not on standby, but ready to see an unrequested product disappear or a collective project fail, that's another matter. We might still judge you harshly--for having terrible judgment about the worth of the project--but you wouldn't be a freerider. You might even be something worse, but you wouldn't be a (bad) freerider.