Well this is the 6th Gen ES thread which would mean they have keyless ignition. :-)

 

The reason why I pointed out that the caution only applies to those with keyless push button start is that Jollick indicated that he has not had any issues with storing the key near the vehicle with any of his Lexus vehicles since 1998, but only the more recent of those vehicles would have had the keyless push button start.

It should also be noted that a base bare-bones 6th Generation ES without even the Premium Package does not have the push button start. I've never seen such a vehicle, and I'm not sure how many of them Lexus actually builds, but, theoretically, they are available.

 

As noted below, I have a 2013 and 2015 at the present time, both were purchased new. I think the OP hit it on the head saying that actually means keeping it very close like 10 feet or less.