Don't know why I'm posting this as it's not my decision and has no bearing whatsoever, probably, but here goes.
My reason mirrors the other user(s) that have stated that its part of the fun of vanilla.
I kinda thought the purpose of a mod was to modify. Push mode, too, takes away part of the freedom you had in vanilla as you can no longer just take any control point but rather find yourself restricted to one or two, but I hardly see anyone complaining (I think Steve/Stevanyss' complaint is the Two Credits rant is the first I've ever seen about this issue). Removing parachutes takes away from the "fun" and "open-ended gaming" of vanilla, but still it's been done. Restricting some weapons and devices to squads only takes away from the trademark "fun and openness" of the Battlefield series - it's still been done, and I hear no complaints. Locking the probot takes away from...
You get the idea.
Yea its frustrating when a couple players base rape you but if your team is covering the bases that wont happen. Also I like where in vanilla you can spawn into a vehicle unless its been stolen.
Whatever you might want to believe, it's not feasible other than in theory to 'cover your bases'. In effect this'd mean having at least one person spawning there doing absolutely nothing until a vehicle arrived, just so you could keep that random lonewolf from taking it. Next to no one is willing to do this.
It's like the old Hoth map in GC, where the Imps could just sneak into the Rebel command centre and proceed to have lots of Imps spawn there and rape the Rebels in the hangar and then proceed to take the trenches outside in a pincer strike - Imps attacking south from within the base with infantry and speeders, and from the north with AT-STs. In essence, this allowed them to win the round with no effort at all. Sure, it was easy for a lot of people to say that it was the Rebels' own fault for not covering their bases, and sure, making the Imps have to take trenches (or was it the hangar?) before the Command Centre "took away some of the freedom that made vanilla fun"... but again, I never heard any complaints.
Why? Because "covering your bases" works in theory, but the few times I volunteered to do this in GC, spawning in the Command Center on Hoth doing absolutely jack s**t for up to half a round just in case some lone smacktard decided to try to sneak in... was not fun. Likewise, "covering your bases" in FS map is not fun, which is why we have push mode maps. It's the exactly same thing in my eyes. It's not fun in being massacred by your own team's Assault Transport just because some noobflake on the other team happened to see the grey icon appear in your main base a second before your team did.
So my view (and I want to stress that this is my view only and does not reflect that of anyone but me), is this:
• All vehicles locked until occupied by someone who owns them. Light vehicles such as the AT-ST and Combat Speeder can be stolen once occupied and abandoned.
• All heavy vehicles (tanks, whatever transport aircraft we might add such as the Assault Transport or Lambda, bombers, X-Wings, etc.) locked at all times.
• Starships and transports locked at all times.
• Probot remains locked.
There's also the "authentic SW experience" argument. I would strongly dislike hearing the infantry in the trenches report "Imperial walkers on the north ridge, massacring the Imperials". Stealing vehicles very easily ruins the flow of a map.
Hey If you left a tank running with the keys in it in Iraq you think the insurgents wont take it?
You bet they wouldn't.
"One of the bitches actually gave birth while she was attacking, and her puppies joined in on the carnage."
--the awesomeness that is Boatmurdered.