My son's christening...

[Chas]

A fly plaid can be a bit of problem. You have to get the balance just right, otherwise it will try and lift your jacket up and off your shoulder. The other consideration is the brooch. If you intend to hold your child in your arms, there will be this lump of metal (and maybe sharp stone) just where his head will be. You could end up fussing with it all the time, rather than enjoying and taking part in a joyous celebration.

Regards

Chas

[English Bloke]

A fly plaid wouldn't work with the jacket I have (and you will have). You would really need an epaulet to thread it through to stop it falling off your shoulder and a simple modified suit jacket won't have one. As Chas also mentions, they are a fuss apparently and require constant adjustment and you have better things to worry about. I wouldn't if I were you. Go for comfortable not fussy.

Now that's out the way, I think Ron (Riverkilt) was referring to your mode of transportation rather than your attire.