It must be nice to be speedy enough you don't have to worry about that. And that you've been lucky enough there has never been an issue with not enough volunteers showing up/signing up and/or there being an issue with delivery to the water stations. I've volunteered at enough races I've seen it happen - delivery driver gets lost, there is traffic prior to road closures, even a race vehicle doing a course pre-check running over a hose filling the barrels and causing 4 volunteers to be injured and taken to the hospital because the hose flipped them (happened at a station I was working at during a race - I was supposed to be heading the cheer squad there but we all ended up pitching in for the fluid station and we barely got it set up in time because we were down those volunteers along with 2 who went with them (one extra per ambulance).
When you're more towards the back of the pack and have seen stations closing up well before the cut-off time, you learn quickly. And it's not just hydration. In 2014, runDisney First Aid stations as early as between Animal Kingdom and ESPN had run out of BioFreeze - and I was rear mid-pack at that point. I've been in races where the stuff was set out for people to grab and they did not monitor it enough so that early runners took EVERYTHING. In that case, the volunteers were kind enough to go and get fruit to hand out, but when you haven't trained on fruit and were counting on gel...it's not always a good thing.
Bottom line is I NEVER want to depend on something being there when I can provide it myself.
If your circumstances dictate that carrying your own is a good idea for you, by all means, go for it. I specifically said I wouldn’t discourage anyone from doing it. In your earlier post, you said you didn’t “get the mentality of not taking responsibility for yourself”. I wasn’t criticizing your decision to carry hydration, just trying to give an explanation as to why many choose not to.
To address your examples, too, I’ll expand on my explanation. First, thank you for calling me “speedy”! I don’t get called that very often at my typically mid-pack pace.
Yes, pacing and pack position play a role in the “carry/don’t carry” decision making process. Personally, I find it inexcusable that water stations may run out of water or be shut down early. All runners within the pacing guidelines of an event should be guaranteed the same level of support as everyone else. But that’s a discussion for another time.
As to the examples of hydration stations running out or not being manned, those can certainly happen. Unless the race is terribly mismanaged, though, they are typically isolated issues. Water stations are generally set up every 1.5-2 miles, in my experience. During my training, I routinely run up to 6 miles without hydration in high temperatures and up to 10 miles without in cooler temperatures. Due to this, a missing hydration station or even two isn’t going to impact me significantly.
Again, none of this is a criticism of anyone’s decision to carry their own hydration. It’s just an attempt to explain why I, and many other racers, don’t find it as critical to carry our own during typical races.