That is not how trips are used, they are replaced multiple times depending on what part you want to hold. Any good high-rank experienced sentinel main places trips further behind during a default. You still have map control and can still hear someone if they try to dodge the trip since you wouldn't be as far inside as the site, rather you'd be nearer to A main. And they will pull back the trips and place them closer after the team has committed to a site attack bcoz in a post plant I don't care about that space
This is literally how trips are used and it's nothing new, they have been used like this forever