Double spend transactions flag the node as "bad"? I'm playing with raw transactions. It's easy to send two signed valid transactions at the same time from the same output to different addresses (making a double-spend attack). My doubt is: if I make tests like this, will the bitcoin p2p network will flag my node / IP as "bad" or I can do it normally without any consequences? Of course I am not attacking anyone else, I want to make tests with my wallets / system to see the behavior.
Your current peers can ban (for some time, not forever) your IP-address.
Just connect to other nodes in case.
The network itself can not do anything with you because there is no such thing in protocol.
Your peers do not know - are you a double-spender or you just relaying somebody's else packets.

(Sorry, my English is also very poor)