Yes, its possible to bid in the last 10 seconds w/o a sniper tool but you have to be present. But in last <5 second its almost impossible w/o a sniper tool.
Sniper tools were forbidden for a long time by eBay, but they didnt care. Checked German eBay TOS and it seem its not mentioned anymore. Sure, eBay wants the maximum price, but IMO sniper tools are preventing this in some cases. But for German eBay non commercial sales are w/o a fee now, so eBay dont have a benefit form the maximum price, and a lot of commercial sold stuff is sold via instant buy.