I know they say not to clip that stuff but I don't think I would want to wear a pony tail all day I get head aches from them. Mandy is a pet so I trim them into her topknot and actually keep them shorter then most do as I can't imagine looking through hair all day either. Just me.
Mandys seem to fall in her eyes more then Caseys for some reason his can be a little longer before it drives me nuts and cut them for him.
I don't see very many poodles with eyelashes usualy because when triming the topknot you end up triming the eyelashes. In some cases you trim them wether or wanted to or not. Sine You have dutch's topknot long and tied up I guess his were alk\lowed to grow. Would love to see a pic of them.
I feel like it's up to you if you want to trim them or not. I don't feel like they do major harm either way though if they get really long they can collect "stuff" in them and maybe irritate the eye. Pressumably though they are there to keep things OUT of the eye. It's a 50/50 IMO. If they are pretty and you like them maybe keep them but trim them just a tad shorter if you're worried they are irritating him.
I know exactly what you are talking about, Zoey's did the same thing (see pic) when and I had to redo her topknot every few days because of it, I liked them there because it filled out her topknot a little more and as long as I was attentive in putting them up again when they got to bad, they did not cause any problems. I think it is a matter of personal preferance as well.
It will not matter to much I would not think, he is a spoo right? They have ALOT more hair then my toys, so the fuller they are the better. I got so used to Zoey's being there, when I took her in to get her lamb clip, they shaved them off and not I think she looks like a cone head! LOL! I will grow them back out but keep them trimmed to stay up out of her eyes. My next poodle I will keep them as well, it is just personal preferance. If you started clipping them as a pup, and want to grow them out to add to the fullness of the "bubble" since they are more sturdy then the hair they seem to hold it in place well, you can always just use a little mouse to make them stay where they are needed. Here is a pic of my Zoey's win before she was diagnosed with the LCP her eyelashes were long here.