Being hired by a client is a recognition of your skills and a tribute to
your professionalism. Regrettably, clients don’t always use you to your
full potential. Perhaps they ask you to resolve a problem a certain way,
contrary to your beliefs or even industry best practices. Maybe they
express little interest in a growing problem you’ve uncovered. Whatever
the case, just remember: the customer is always right.

Put another way, give ‘em what they ask for. It’s not a
freelancer’s place to make decisions. (Even if you were hired to make
decisions, in the end it’s really the client who gets the last word.) That
said, you don’t have to turn a blind eye to problems. Bring it to the
client’s attention and get them to decide:

First, do your research. Ask around: has this problem been noted
before, but solutions were vehemently rejected? Maybe you have this gig
because your precessor was too vocal about the change.

Next, explain your idea. Bring it to the attention of your immediate
manager or team lead. Start with an e-mail and, if they’re interested,
setup an informal meeting. Explain the situation in their language: “what
I’ve found will hurt (read: dollar signs). Here’s how and why. Here’s one
alternative I’ve cooked up, and here’s how/why it may hurt you less in the
long run.”

Your client may make a decsion partway through your pitch. To paraphrase
some sage advice, stop when you’ve won them over or when you’ve lost.
[1]

Don’t forget to get it in writing. (Does that
ring a bell?
It should.) Save any handouts or diagrams you provided in your meeting, and
follow up with an e-mail to recap what was discussed. Maybe you can reuse
them in a presentation to other management types. In the very least,
you’ve covered yourself in the event their chosen path turns out to be a
dead end.

Give them time to decide. You’ve stated your case, so there’s no
need to mention it again unless specifically asked. It’s up to your team
lead to pass it up the chain to their management, and so on, until
something either happens or the problem is shot down as a non-issue.

Finally, know when to fold ‘em. Some clients will be gracious and
grateful for your sharp eye and willingness to help; others will insist on
ignoring your advice. Others still, considering their long-term plans,
will acknowledge the problem but concede that it is dwarfed by some other
business need.

Accept your client’s decision and move on. Not only do you lose any and
all turf wars by default — you’re on the client’s territory, don’t forget
– but merely starting one earns you a reputation as someone who oversteps
their bounds. That’s a black mark your reputation could do without.

Most of all, resist the urge to make unauthorized changes in the name of
helping out. Some clients will immediately terminate your contract.
Others are more subtle and simply opt against a future renewal. (”The dog
ate my homework.” “I can’t go out because I’m washing my hair.” “We have to
let you go because of budget cuts.” See a theme?)

Avoid being helpful in a way that gets you canned. Take a slow, structured
approach to inform your client of potential pitfalls and you can come out
looking like a pro. In the very least, you can walk away from a situation
knowing that the client got exactly what they wanted.

References
[1] = Career Warfare, David F d’Alessandro, p140: “The most
common way in which people sabotage themselves in combat meetings is by
continuing to argue when it is time to either admit victory or dmit
defeat.”