It depends where I am and what I've got with me. In town, I'll lock the bike and take the computer module with me. If I'm using my lights, I'll take them as well. I keep tools and patches in a small saddle bag or a rack trunk. I'll just leave that on the bike.

If I'm in a larger centre, I'll lock the bike securely and take my rack trunk with me. I've never had a store clerk question me about carrying the bag.