Totally without any scientific evidence and based only on my own limited experience, but here goes:

Most aftershave you can find in the shops is targeted at the other shaving markets, and not at the straight razor users. It does not need to perform in the fashion we need. In days of old, after shave treatment would be cologne (originally called "water from Cologne") which was a specific alcohol and citrus oil blend containing just a small fraction of scent (1-2%). Store bought aftershave of today often has a higher content of scent oils than these old school colognes. Personally, I find store bought stuff chiefly unsuitable for straight razor shaving. Today, the term after shave might even mean Eau de Toilette, which has a far higher percent of scent oils. Before I started straight razor shaving I would use the regular aftershaves just fine, but when shaving with a knife I want a splash. Using an eau de toilette as a splash certainly might affect your surroundings and upset your better half - I know this from experience
On a side note: I do believe that Bay Rum and the similar old scents are better suited for us, being made from the old recipes and intended to be used as after shave splashes.

Enter my home made solutions.
High alcohol content is nice for us, because it helps close the pores and also disinfects and help us keep healthy. The drawback is that alcohol also tend to dry out your skin.
I solve this by using a shea butter moisturizer after the splash. I made my own, and it is unscented. I've also tried diluting my old after shaves with pure alcohol, it works fine to kick down an overpowering scent. I've also tried using witch hazel, not to my liking and now I just use an alcohol based splash and a moisturizer after, works fine for me.
The thought has occurred to me as well to make an unscented after shave splash - I have not tried yet but if I did I would try something like a spoonful of witch hazel in a cup of alcohol.