I believe the term you're looking for is spawn-camping, and it's in just about every shooter ever. In general, it's a good way to shut out incompetent opponents on a badly designed map, but harder to do against good opponents on a good map. Harder still if you're outnumbered because your teammates are busy elsewhere, and it's a bit risky since as soon as you die you have a long trek back, giving them an opening to escape. However, in this game Super Jumps will help with that if you can keep at least one teammate alive up there.
The chokepoints on Walleye Warehouse are so cruel, it's a very easy map to camp. But instead of having one teammate go all the way up to spawn while the others go back and get what's behind him, it would be more effective to capture the middle first and then just have all four players hold the forward chokepoints until time runs out. And that's what I saw happen in a lot of matches.
AFAIK, the spawn points on Saltspray Rig have one-way exits so you can't reach them. You could try to hold the exits, but they seem a bit too wide open to choke. I don't think it's remotely feasible on this map.