I would definitely want to know about it! On the occasions I have heard about YYSL string breaks I either asked about the specifics or asked the person to send it to me for analysis (in exchange for a full pack for their trouble). On the two or three occasions that I received the broke string, it looked more like a cut exactly where the edge of the response would be, not like a random frayed separation of all the strands. I can imagine a new string break happening with cotton, but the rare flaw in poly, although trash bin worthy, would not cause the other strands to also be significantly weak (it would just be like using a thinner string as far as strength is concerned). Now, keep in mind I am talking about a relatively new string. I would imagine that for a poly string to get that weak, it would have to have been thrown a bunch or have been snagged by something sharp.
I just had a cotton string break on me last night. I was having a lot of fun with my Legend Wing and forgot to check the string 
Cotton strings break on me like clockwork. Cotton strings are bad and should feel bad.
It was so nice to play with and then it betrayed me. Afterwards I put a poly/cotton blend on there and it’s alternating between responsive/unresponsive every other throw. I landed a brent stole on this thing in between knucklebeatings. 
I disagree. Cotton strings aren’t bad.
Well, if you like randomly flinging your yo-yo into a wall, the ground, a ceiling fan, random passers-by… then by all means use a cotton string!
Cotton strings break like crazy for me and consistently! Poly on the other hand has been rock solid. I don’t think I’ve ever had a poly string break, outside of some rare string eaters that had too rough response areas.
I honestly don’t know what you do to them to have them break on you so much.
I will say I’ve been going back to cotton more and more lately. Especially for wood, but also with my 650b’s. I just… prefer the feel. I haven’t broken a string in years with any material (as much a function of throwing mostly stall-based tricks as hardware I’m using). Also, in a world where I bring reusable bags to the grocery store and avoid purchases based on how much plastic the packaging contains, there’s something to using a plant-based biodegradable string lol.
To each their own, but cotton works great for everything I do.
One say you will realize your dream and become a tree again! Well, some of your molecules will anyway…
Didn’t Rick Wyatt break brand new strings on his first throw? Going for the sleeper record I believe for sure. If you saw him throw a sleeper you’d believe it, people would take cover.
I once had 3 poly strings break in a row after about 10 minutes of play on my sage. I had dropped one half of the Yoyo the night before, and apparently it left the tiniest little ding just above the response pads. Could t really even see it, but it had just enough abrasion to saw through the string. I sanded the ding out and it hasn’t happened since. Luckily it was happening on wood floors and at the bottom of my break away, so it just flew across the floor and rolled right back to me almost every time lol
Some applications such as fixed axle call for cotton. The trick is to listen carefully, before cotton breaks you will usually hear a couple of strands break (snap, crackle, pop). Then it’s time to change it out. Also periodically inspect it for wear. Strings usually break for me when looping, and the majority of the time it’s at the finger loop, very rarely at the axle.
Interesting, cotton strings always break for me at the axle loop!
Has anyone ever made 
string out of silk? Naturally smooth
sounds expensive 
So are Titanium s , there probably is a niche market if there are performance and functionality benefits. Let’s not count out the luxurious of it as well.
Some has done it in the past Some string I made... (Silk string on Page 2) - #21 by Newbies_United
I was using my first Yomega Glide at a fancy party at our neighbours. I showed them some moves until my cotton Duncan string decided it had enough. It shot across the floor making a terrific racket. My parents were not pleased.