rapid -- not necessarily automatic weapon -- fire in some ambush counteraction or surprise situation. However, in my observation, there's no 'rule of thumb' as to when and where to use the technique. Each situation and terrain set poses variables. For example, in a jungle setting, a turn into the ambush positions and rapid semi-aimed (never spray and pray -- so jcustis is also right IMO) and an assault will often be beneficial. If, however, you have a really competent enemy, they will have anticipated that if your forces use it as a technique of choice and will have mined or otherwise prepared to prove that's not always a smart choice.

Won't work too well in urban combat. Or in some cases in the mountains. Equally obviously, trying that in the desert or any open terrain -- or in deep snow -- will put you at some risk...

Immediate Suppression by Artillery can be still used, it isn't necessarily for ATGM crews alone. Conducting a good aerial, ground or just a map reconnaissance and establishing targets at likely enemy positions along a your movement route long predates ATGMs. It is really effective, particularly in those big open areas and the Arctic or heavy snow though not so much in Cities, Jungle or dense woods...

METT-TC...