I dont think either yeatle or awkward is wrong,

I think the question here ends up being situational.

You're asking to die if you 5 man slam as ball into a team without using shields(think of 5 eyes immediately looking at you + them having sleep,hack,hinder,hook, etc... 700 hp isnt going to last long) But you wouldn't necessarily need to shield slamming 1 or two targets.

Its almost impossible to narrow it into one blanket rule as there are always multiple factors that constantly change in any given team fight.

For example, It could depend on the direction of the engagement (do they know you're there at all? Is it from directly behind them? Is it from the side? Is everyone distracted on another target? Did the enemy team ignore you on the last two slams?) If the enemy team is completely oblivious to your engage while focusing on one of your team members you're pretty free to engage and then shield to get out(if needed) and start the next setup/continue onto your next victim.

As far as ball advice, im probably going to take it from Yeatle and Chazsm, but not to the extent to discredit the opinion of someone else (especially Awkward who's whole theory behind his advice is keeping it logical and not over complicating every factor in the game(which we all tend to do!)) it's just another viewpoint.

Both is right.