I feel that commanders should not be able to tag up for hours upon hours in wvw. Its very unfair to other commanders who would like to tag up on the map. It's even worse when commanders jump maps and upon returning to the original map, demand that whoever tagged up in the interim tag down.
If a commander challenges these commanders who are tagged up forever on this, I've noticed many of the followers of their squad or their guild mates bully whoever was trying to tag up, sometimes mercilessly.
I think commanders should have at a maximum a 1hr tag time followed by a mandatory 1 hr to 30 min tag down time across all wvw maps, so that other commanders get a chance. Other commanders would like to participate and get the extra pips too without being harassed or having all of the commanding monopolized on all maps by one person.