Just tested this on 4 new accounts, 1 main that I bought a while ago that I've been saving. I've used 4 different proxy providers that supply fresh, virgin proxies, and tested this script on all using various methods and various fishing spots.
All 4 accounts were banned. 2 were banned permanently, and the remainder were banned for 2 days with a non appeal-able bot busting ban.
For One account I was fishing Barbarian Fly fishing, caught within 7 hours, including 1 hour and some minutes break. Stealth injection was on since mirror mode for this is extremely slow and somewhat noticeable. It was permanently banned.
The second account was fishing minnows, banned again. Stealth Injection once more. This account had random stats, some 70+, name was authentic, and had never been botted on with any other scripts. Perma banned.
The third was fishing minnows also. This account was the most noticeable, I botted the account all the way to minnows and suicided it until it got caught. The total time for fishing at minnows was 21 hours. Breaks included, I can't remember how long. Funnily I only caught a 2 day ban with this account.
The fourth was my main, fishing minnows again, this time on mirror mode, 50ms delay. Banned within 3 hours. 2 day ban.
All the accounts were made 1-3 years ago, besides the suicide account. All the accounts were using fresh proxies. All the accounts were banned. All the proxies came from different providers, all fresh. Granted I can't say atleast one of the proxies may have been detected, it'd be extremely unlikely that all the accounts IP's were detected. There is something with this script that is getting caught. I'm not saying it's a bad script, I'm just saying there is a high possibility your account will get banned if you use it.