If there's a disturbance which Dumbledore suspects is a distraction, why did he send only Snape, rather than several aurors/coming himself?

Hypothesis: the situation is a trap for Voldemort. The corridor itself is blatantly a trap - it's easy to enter, but we know from Fred and George that it's full of invisible wards. Voldemort wouldn't risk confronting Dumbledore, and an unguarded corridor would be too suspicious, but Snape is just right in terms of difficulty level (and also has the option of going "my lord, you have returned!", surviving an encounter which would be fatal for anyone else, and possibly sneaking off to call Dumbledore).

The flaw with this is that the trap is really obvious, and Voldemort's intelligence is known to be very high, so it's implausible that he would enter the corridor at all unless he was absolutely certain of being able to steal the Stone despite the wards, and before Dumbledore could return.