I think All broker wouldn’t know wether you are using EA or not. But some EA use hedging algorithm, and the intensity is very high, that is how broker AI logic determined wether you are using robot or not.
They know you use EA! even what kind of EA you’re using. However, there are brokers who will not care about your EA and only exclude those on their blacklist
Brokers do know you use an EA and do not care at all . Some EAs win, some loose. No different to manual traders
I think they know even more than they need to and really see whether you are working on your own or using some algorithm. But in fact, if the company rules don’t prohibit it, you can use it in your work without any restrictions.
And what does it matter?
If you work with a normal brokerage company, you can act as you like and get the desired result.
This is the most important thing…
Some EAs even have a stealth mode. Although I cannot comment on its effectiveness.