It's pretty funny how serious people take the internet. Someone gets called out, then goes I'll show these guys, makes a sign showing it's him, makes a video and goes through trouble of posting it on youtube. Give me a break. If someone doesn't believe you lift what you lift, fcuk it...... It's the internet it ain't that serious. Brutal self esteem issues.
People could also say that you had a big guy in the gym do a favor for you in exchange for a "favor".