I have conflicting thoughts... If the clean out plugs partially dislodge... The tubes won't save you. The pressure is so great the water will overcome the tubes and will fill the boat with an enormous amount of water very quickly. So the tubes won't save you from this. If you are worried that this will happen, you need EZ Locks. They will prevent the plug from blowing out in the first place. This is my recommended mod #0 for our boats.
However, the tubes will ensure the water that normally washes over the transom platform will be directed to fill the tubes until they are full, and any additional water will leave via the tray drain. If the plugs are in good condition, (If not, go ahead and rebuild them) the advantage gained by not having these tubes in is minimal. It is more comfortable to put the plugs in without this tray or tubes in place, but agree with others that it's too big a hole way too close to the water line to be acceptable. This is not cool and needs to be remedied right away.
Putting them back in is probably a 1-2 hour job if you do it slowly. If I had to go out the weekend before I had a chance to put them back in, I would make sure my bilge pump was working perfectly, and I would probably risk it for the ONE weekend... but that's just me. If your boat sinks because of it, this advice was crap, but is what I would have done myself. How lucky do you feel?
So, my humble opinion...you need to put them in as soon as reasonably possible. preferably yesterday.
(My mod
#1, after mod#0 EZ Locks, is a bilge float, alarm and extra bilge pump. Different topic, but not so distant. It can turn a mistake or small issue into a non-issue vs a really bad day with a sunk boat.)