Originally Posted by Spring Pools
You wouldn't see any lead because Yonex puts the lead in when they are making the racquets for players.
They don't put lead when they're making the racquets to weigh more, they actually use different materials than lead, such as high modulus graphite, Kevlar or anything they know that can add the desirable weight where their players want, that is only when Yonex players have reached their preferred set up and no longer needs any customization.
Some players don't use any lead some do, but the racquet is the same for those who use the model, in this case Wawrinka, Juan Monaco, Go Soeda and Tomic use the same racquet but of course all of them have their preferences so it would be natural for all of them to use the same racquet with different weights, balance and so forth.
To prove you that some Yonex players use lead and Yonex not always does what you think here are some links. Bear with me, I don't know how to post pictures straight here.
From Monacos Facebook, this picture shows the lead @ 3&9 I had seen it on TV.
Maria Kirilenko's racquet with lead tape RQiS 2 Tour:
Zheng Jie's racquet- Lead @ 10 & 2, from Yonex facebook's page. I also saw this on TV.