the point is not whether you may "pull a hammie", but (1) why some people are so stupid to use (tiny) weights they cannot handle, (2) why not ask for a spot in advance. i am more than happy to spot if somebody asks and i do not care about the tiny weight as not long ago 135 lbs crushed me too. but i never got to the point, whether it was 135 or 315, when i could not finish a rep. when i am not sure, i ask for a spot or do not go for another rep. it's that simple.
one exception to the above: several times i got crushed under a weight out of curiosity as i wanted to see how hard it is to get from under the bar myself when nobody's around. this gives you extra confidence that it is not a big deal, well, at least up to a certain weight. same with squats, when i was training a friend, i made him go deep down and drop the weight (usually 95 lbs) so he could not get scared shitless in the future when the weight gets heavier. some folks are too "shy" to do a dynamic movement with their body so that the bar does not hit your spine, and they are also too afraid of the noise they will make. fvck that. show these skinny bitches right now how to handle light weights before it is too late and they seriously injure themselves.