I've been getting these emails from LL since yesterday : Your Second Life account has been accessed from a new machine. If you recently logged in to Second Life from a new machine you may ignore this mail.

I always use a VPN and also spoof using Hydrastorm settings but my question is : Could this raise any flags on my account ? Is LL going to think somebody is trying to hack my account or anything and block my account ? Just want to make sure it's not going to happen

VPNs might change IPs sometimes,and it looks like you accessing from somewhere else than ususal.If you spoof and change MAC or ID sometimes,it looks like new netwrok card,or computer accessing.If using a virtualmachine to sandbox,it'll sometimes give different internal IP or network IPs,or sometimes computer hash.

Strange that you got this e-mails never had a e-mail like that, even i switch also from computers,
Linden has nothing to say about that, 
maybe its a spam so becareful, look to the sender before you change or open something,

yea i got one i ignored it