Here is your solution. (if you don't use a magnet key box, etc)
Go have a copy of the key made. (Withouth the ignition key/chip in it).
They el-cheapo $1 or $2 dollar key copy. Yes I know that won't start your car.
But it will open your door.
But take the "copy" of the key with you diving. It WILL open your car door when you return.. After you get your car door open, you can then retrieve your ignition keys from under your seat or trunk or other "hiding place". (just not out in the plain view open).
You'll find this easier because
1.) you will only be carrying one key instead of your keychain
2.) you don't have to worry about loosing or getting your keyles entry wet or sandy.
This is also a good key to use as with the magnet key box other times..... It will allow you entry to your car, but won't let a thief start it. (Of course he can still steal your CD's, etc.)
this help?