I might sound like I know what I'm doing but it's just an illusion
RE: throttle lock.
I agree it's not something that newbies cutting their first log should attempt right away.
However, its definitely not a problem for the saw as cuality correctly tuned chain saws are made to run full throttle for extended periods and the load controlled by pressure on the wood and not the throttle.. The most common thing I see with newbie operators is they think that saws shouldn't be run like this and sit on 3/4 throttle thinking they are are saving the saw. Once the cut is established, slipping a slightly loose cable tie over the trigger is no big deal and has been done successfully for many years by site members and I haven't heard of anyone on this forum having a problem with it.
Another important reason (especially for newbies) to stand on the power head side of an Alaskan mill is the power head will get caught up on lumps and bumps on the side of the log, or the chain just grabs too much wood and jams. Trying to direct the weight of a power head or unjam the mill from the other side of the log requires much more strength and leverage than standing right next to the powerhead.
It's different for mills on rails where the rails provides the side ways support and the powerhead is not in direct contact.