"Like-gating" is a behavior that I find pathetic; it dilutes what little value there might have been to tracking "likes" to begin with.
If you actually care how valuable your brand is, you won't give anyone a damned thing for "liking" you and you won't make it a condition of doing anything else. What good is a disingenuous opinion about your brand? You should only want a "like" if someone gave it to you without being asked.
I think you misunderstand the purpose of getting a Like in this example: it's not for social proof, but to create a more direct relationship with the "fan" so that when you post on your Facebook page they become part of the conversation.
Think of it as collecting an email from your customer, it's disruptive to the process of trying the app and some users will not do it, but it allows you to talk to the ones that do submit, helps build a better product in the long run and keep those same users happier.
Customers should not see walls or spam. Intentions are irrelevant if the outcome annoys people.
What part of the verb "Like" would make the customer think "oh please make me part of a conversation"? I would go as far as to say it is obvious they wouldn't expect that outcome.
If you put any roadblock at all between your customer and the acquisition of your product, you will lose some customers. And you will never know how many because they will silently think "to hell with that" and never return.
If you subsequently spam customers with updates, they will start regretting the purchase and make a mental note to never buy from you again. Once I bought a pair of sunglasses and began receiving spams once a week from the store (seriously, how often could I possibly be interested in sunglasses, especially since I just bought a pair?).
It may be a hard pill to swallow, but there is no reason for a customer to give a damn about a company on a regular basis unless it's a product that can be consumed really often (like maybe going to a restaurant every few weeks). If it's something that people may buy only every few years, they don't care about you and they don't want to hear from you.
Facebook pages and other sites already have ways to request updates, e.g. the "Get Updates via RSS" link. Unlike abuse of "Like", the updates link is clearly labeled and it does tell the user what will happen when it's clicked. It is also correctly off to the side where it's available for those who need it and not in the way for those who don't.
If you actually care how valuable your brand is, you won't give anyone a damned thing for "liking" you and you won't make it a condition of doing anything else. What good is a disingenuous opinion about your brand? You should only want a "like" if someone gave it to you without being asked.