user33924: Let's say current BTCUSD rate is 1BTC = 3,000USD and average fee is 300satoshi per byte And I need to pay some bitcoin to P2PKH address owned by bitcoin exchange/cafe or bar, basically whoever allows Bitcoin payments.
Because Bitcoin allows that transactions which has multiple same address output, I can do something like this

Input


0.0135 BTC($40)

Output


cafe address 0.00045BTC($1.332)
cafe address 0.00045BTC($1.332)
cafe address 0.00045BTC($1.332)
... 27 more same outputs


I need to pay about $9 extra fee(because each output are 34 byte data therefore each output costs $0.306 (3000 * 0.00000034 * 300)).
Once the transaction is contained in the blockchain, I technically paid 0.0135BTC and I get a cup of coffee.
The problem is, the caffe owner almost never be able to use it.
each P2PKH input needs around 148bytes and costs 0.000444BTC(0.00000148 * 300) as fee.
spending 0.00045BTC requires 0.000444BTC.
I don't know who would do this.But this might work.
Could this be happened?

user5757: Technically, sure, this is possible.
Practically, you might get away with it the first time.  You'll have effectively paid an extra $9 for your $40 round of drinks, but you'll get the added satisfaction of having been a jerk.  The bar owner will realize that he can't spend the money, shake his fist, and write off the cost of the drinks (which is probably more like $10).
The next time, you'll find a sign posted that says "Bitcoin payment rules: maximum one output".  If you try your multi-output trick again, they'll point to the sign and say "nope, that doesn't count, you haven't paid".  You'll have to pay again, and now you are out $89 for a $40 round of drinks.
(The third time, you'll find a photo of you behind the bar, marked "DO NOT SERVE".  And a very large fellow in a T-shirt will ask you firmly to take your business somewhere else.)

33924: <p>Let's say current BTCUSD rate is 1BTC = 3,000USD and average fee is 300satoshi per byte And I need to pay some bitcoin to P2PKH address owned by bitcoin exchange/cafe or bar, basically whoever allows Bitcoin payments.</p>

<p>Because Bitcoin allows that transactions which has multiple same address output, I can do something like this</p>

<ul>
<li>Input

<ul>
<li>0.0135 BTC($40)</li>
</ul></li>
<li>Output

<ul>
<li>cafe address 0.00045BTC($1.332)</li>
<li>cafe address 0.00045BTC($1.332)</li>
<li>cafe address 0.00045BTC($1.332)</li>
<li>... 27 more same outputs</li>
</ul></li>
</ul>

<p>I need to pay about $9 extra fee(because each output are 34 byte data therefore each output costs $0.306 (3000 * 0.00000034 * 300)).</p>

<p>Once the transaction is contained in the blockchain, I technically paid 0.0135BTC and I get a cup of coffee.</p>

<p>The problem is, the caffe owner almost never be able to use it.
each P2PKH input needs around 148bytes and costs 0.000444BTC(0.00000148 * 300) as fee.</p>

<p>spending 0.00045BTC requires 0.000444BTC.</p>

<p>I don't know who would do this.But this might work.</p>

<p>Could this be happened?</p>
 5757: <p>Technically, sure, this is possible.</p>

<p>Practically, you might get away with it the first time.  You'll have effectively paid an extra $9 for your $40 round of drinks, but you'll get the added satisfaction of having been a jerk.  The bar owner will realize that he can't spend the money, shake his fist, and write off the cost of the drinks (which is probably more like $10).</p>

<p>The next time, you'll find a sign posted that says "Bitcoin payment rules: maximum one output".  If you try your multi-output trick again, they'll point to the sign and say "nope, that doesn't count, you haven't paid".  You'll have to pay again, and now you are out $89 for a $40 round of drinks.</p>

<p>(The third time, you'll find a photo of you behind the bar, marked "DO NOT SERVE".  And a very large fellow in a T-shirt will ask you firmly to take your business somewhere else.)</p>
