Nope. Total control over the machine is what matters most to MS and Sony. Piracy may even have helped sales, every year everyone that gets banned buys a new console.. but Microsoft makes billions of dollars with very little production costs with Live. If everyone's machine was JTAG'd, M$ would really be pissed.
Notice how the JTAG exploit was patched before it was released, by blowing efuses. Meanwhile every single version of the 360's optical drives has been hacked to play backups.. even the slim / s / 250. If Microsoft wanted to stop that, they could have paid $3 more for the DVD mobo's to have non-writable firmware... stopping the piracy instantly.
Control over the core system is what matters. Once that is lost, hackers can do anything they want, and that is what scares MS and Sony the most.