Does 14 CFR 91.146 (Charitable Events) apply if the pilot does not seek compensation or hire?
Let's look at this from two angles -- first, what's OK under 61.113 (basically &quot;no compensation except the pro-rata sharing of expenses&quot; when acting as a private pilot).
The FAA has an incredibly broad interpretation of &quot;compensation&quot; - The foundational counsel opinion is an interpretation to Joseph A. Kirwan, and if you search counsel opinions for Kirwan you find a bunch of additional opinions referencing it.
Basically Kirwan and the other opinions state that the receipt of anything of value is compensation.
That could include:

Money, obviously.
Free or discount fuel/oil
Free meal
Lodging
Logging of flight time (if you're not responsible for the operating expenses of the aircraft)
The receipt of a benefit (usually money) by the organizer (charity)
(Weybrecht, 2010 - if they get the ride in exchange for a donation or attendance fee it's 91.146)
&quot;Valuable Good Will&quot;
(Again in Weybrecht from above - so yeah, If you fly your buddy somewhere and they &quot;owe you one&quot; that might be a violation.)

There's really almost nothing you can do under 61.113 except fly somewhere for a hundred-dollar hamburger and split the cost of gas (under the FARs you even have to pay your pro rata share of the burger) - it's very restrictive.

Now let's look at 91.146 - like DJClayworth pointed out what this  basically does is carve out a small set of exceptions that allow community groups and charitable organizations which have friendly pilots to offer &quot;airplane rides&quot; in exchange for a donation without being in violation of the FARs (risking the friendly pilot's certificate, and the possible wrath of the FAA on the organizer).
There are lots of restrictions (Like the 500 hour requirement, the requirement that flights be &quot;Nonstop, beginning and ending at the same airport, and within 25 miles of the airport of origin&quot;, the limit of reimbursement for the pilot being &quot;pro rata share of expenses&quot;, and notification of the local FSDO).
The FAA wants to basically make sure pilots are not flying tons of these charity flights every year to basically build time, and that charities aren't operating de facto air tour companies under the exemptions of 91.146.

So what's the answer to your question?
Basically If the organization is getting donations/admission fees/raffle proceeds, etc. in exchange for these flights the operation falls under 91.146 (because the charity is receiving compensation -- the donation).