is it ok to fart in a store if no one is in the aisle?

Sometimes it can't be helped.

Fart wherever you like. Everyone farts about 14 times a day. You can't always choose where to let one rip. It is perfectly natural and does no-one any harm.

Don't try it! I did that one time. I thought there was no one around, so I vented some gas, and it was NASTY. Just as this horrendous odor was filling the whole aisle, three gorgeous women came around the corner about fifteen feet away. Whammo!!! You can imagine the looks they gave me through their tears.

Only if you are going to be on the otherside of the store in 30 seconds.

Fart outside

Yes, if you are pretty it won't smell so badly. No, if you are ugly it will smell too badly, so you will have to step outside to fart.

Definitely. It's always nice to leave a warm patch of air for your fellow shoppers.

Is this like the tree falling in the forest question?

Fart on.

I guess that is better than doing it with someone in the isle. I don't think it is actually proper etiquette though.

sure, go right ahead. if you are as pretty as your avatar it should smell like roses.