Bicycle Mechanics - Tube Sizes: can I use a 23-28 in a 30?

I'm getting various opinions on this.

I went to a shop yesterday to get tubes for my 700x30 tire and realized an hour later after the shop was closed that the girl there gave me 700x23-28.
Two people (one an experienced mechanic) told me this is no problem.
Three people (one of whom said he used the wrong size before and it blew) told me to go back and get the right size.

Is there a consensus on this?

It should be fine. Ideally, you should use tubes within the right range, but those should work, no problem. I've known guys who, in a pinch, have used 26" mtb tubes with 29" mtb tires (ISO 559 vs. ISO 622), and made it through the remainder of the ride. This is an extreme example, but it gives you an idea of what the typical tube is capable of-

Yeah, a 23-28 should work just fine in a 30.

I often use a 19-26 tube in a 32, and it's not ideal because the walls inflate very thin... but it seems to hardly increase the rate of flat tires.

Mostly a problem on very light tubes, not usually sold in upto 28mm
sizes. Problem only if the tube has small nicks in it, usually in the
mm size range that thin out on inflation and pinhole. Some tubes
have these, some don't, probably has to do with manufacturing
processes and handling. Not common but happens which is why
most people get away with size mismatches.

I've never had a problem with that.