Red means that item belongs to someone else... if you touch it then two options depend on the results;
1 you are seen = yes everyone knows, they will offen come and tell you to leave their stuff alone and if they can't reach you for some reason then they will fetch guards to do it
2 if you arn't seen = no everyone doesn't know but is suspicious... if you stay in the area they may confront you about it
results: you can talk your way out of suspicion with a skill check, you can fight your way out of the area killing everyone in your path, you can teliport away before they can confront you [normally results in the guards treating you as badguy] or you can say sorry pal i won't do that again
