I believe improvisers should give suggestions only as a last resort.
In the Death Show, Greg gets a volunteer from the audience to give us his or her wallet or purse and we rifle through it for our suggestion. Twice, that person has said to me after the show, "I don't know if anyone else enjoyed it, but I thought the show was hilarious!"
That person felt as though the entire show revolved around them. And the chances that they come back to the theater (and tell their friends to come) multiply.
I am not the biggest fan of suggestions in the first place, but if we are going to get them, please let them come from real audience members. Preferably someone who's there for the first time. It seems often when someone asks for a suggestion -- before they've even finished asking -- someone I know in the crowd shouts something clever or interesting or funny. Just like on stage, we can't handle the silence.
But this takes away one of the most valuable experiences for those people coming to the show. That experience of watching their suggestion turn into 20 minutes of theater.
This is on all of us. I've seen performers at UCB ask for a suggestion from someone who's never seen the show before. Maybe we could do more of that (esp on weekends). But I do think when we're in the crowd, we could sit on our hands, so to speak. If an awkward pause has gone by, sure, support! Throw something out! But first give those paying customers a chance to be a part of the show.