Depending on the signal provider, some trading signals seem reliable, while most are actually not. The risk of using trading signals solely depends on the individual. I think analyzing the market yourself is the best, so, as to differentiate between good and bad signals.
I have joined some trading signals and they seems legit , and sometimes helpful , why sometimes? Because there are times that they send signals too delay , but the only risk is the delay of time you need to monitor keenly the coins for you to sell in a good timing and price.
And most of them seems legit in the beginning, at least the signal providers I followed for some time. I never took any signal for granted, its important to check every information you got from any place in crypto, its full with scammers, people with wrong intentions. Sometimes good turn to be bad is what I wish to say, and that happens more often then people think it does.
In past few months I don't follow any trading signals, most of them are short time signals which are very risky, this market situation made me to have some mid term positions and even long, then to have short ones. Market is volatile, and for now there are no signs of recovery.