Class Changes at round start

Hi, I just wondered whether it might be possible to be able to change classes all the way up until the hiding period for props is over? I often find my self caught out if I'm joining the server and I get in by the skin of my teeth only to find I have a minigun in my hand and am stuck with it for the round.
Other times it might just be lag, being briefly afk (grabbing a drink from across the room) or forgetfulness which prevent players from being their preferred class in any given round.

Not sure if it's possible, but if it is might this go into consideration?

---Marshii

you gotta go fast man

How do I select class? I wanna be a mechanic.

I shouldn't think this is possible simply because TF2 sees the round as started as soon as the Scouts can move.

Just be mindful in the future.

lol.