In the case that the question is directed to me from someone from the lab, I would normally be polite and ask why he/she wants to do it, or why is not doing "whatever else that would sound better to me", of course, If I know about it. If is a simple task, I would still help, but if it would take me long time (essentially, building a model in jags or TMB) I'll just point out resources that may be of help, as it is not my job to do and I cannot allocate several hours regularly to prototype, test, and polish others stuff, unless the question is very interesting to me too. I would not state things like "this is a wrong approach" or anything similar, because the choice of method could came fro the superior of the person (for example) and I am not a person that would like to generate discrepancies.
If the question is in a general public zone, like here or stack-overflow, I would probably ignore it unless I have very strong thoughts regarding the problem of the approach and the more suitable alternative. A question is a question, and should be answered or ignored, but not changed, as it will remain there for the future and people that may actually need to use the stuff of the question may drop on it though online searches.
There is a bad practice that I cannot stand, naming datasets and variables like my_super_Data_collected_by_me_in_2008 and then my_super_Data_collected_by_me_in_2009 and variables like Tail_length, Time of Day, with consistency close to zero if not negative... for the first time I would politely recommend using shorter names, but for the third time coming from the same person, I would return the data frames as d09, d10 and the columns named V1,V2,V3.... hoping that person would be able to figure out how to rename the columns of a data.frame ha ha ha