Painting something on a guitar will not greatly affect the sound. Putting actual vines on might, if they brushed against the strings.
I happen to be a huge acoustic fan myself, and one of the most popular artist over the best 15 years known for his outstanding acoustic music is Dave Matthes from the Dave Matthews Band. An uprising female artist who solely sings and plays an acoustic guitar is Colbie Calliet.
Guitar Praise happened in 2008.
Guitar Freaks happened in 1998.
PopStar Guitar happened in 2008.
Aero Guitar happened in 2008.
Guitar Hero II happened in 2006.
Guitar Rock Tour happened in 2008.
Well, that matters. If it's an acoustic guitar, and no sound comes out, that could never happen. But if it's an electric guitar you're talking about,either the amps not on, the volume is not up on the guitar or amp, or the cord that leads from the amp to the guitar input jack is bad. You should be able to hear a slight noise from an electric guitar even with the amp malfunctioning or switched off, since the strings do make slight vibrations in airspace anyway. Perhaps they have their hand or arm muting the strings?
sound comes out
Guitar Hero World Tour happened in 2008.
Guitar Hero Smash Hits happened in 360.
Guitar Hero Mobile series happened in 2007.